BTT Road & Legal

How Commercial Truck Maintenance Failures Lead to Crashes

2026-10-07T00:00:00Z

A loaded tractor-trailer depends on a few dozen components that wear every mile: brake linings, slack adjusters, air lines, tires, steering linkages, spring hangers, the fifth wheel. When one fails, the driver usually gets little warning and little room to recover. Federal rules treat that risk as the carrier’s problem to manage before the truck leaves the yard, and they require paperwork showing the carrier did.

Brakes come first

When the Large Truck Crash Causation Study coded the conditions present at serious truck crashes from 2001 to 2003, brake problems led every category: 29.4 percent of trucks had a brake failure, an out-of-adjustment brake or a similar defect recorded¹. That figure is an associated factor, a condition present at the crash, not a finding that the brakes caused it. FMCSA’s report warns that no associated factor should, by itself, be read as the cause of a crash¹.

The study’s analysis brief adds weight. Trucks with brake problems were 2.7 times as likely as trucks without them to be assigned the “critical reason”, the immediate failure that made the crash unavoidable². That is a real increase, if smaller than for driver behaviors such as following too closely. Where the truck itself was the vehicle that failed, the report found the failures concentrated in three areas: braking capacity, tire or wheel failure, and cargo shift¹.

The failure modes that matter most

Air brakes and adjustment. Most heavy trucks stop with air-actuated drum or disc brakes. As linings wear, the pushrod in each brake chamber travels farther before the shoes meet the drum, and past a set point the brake delivers less force. One brake out of adjustment may go unnoticed. Several can lengthen stopping distance enough to turn a near miss into a collision. Part 393 sets maximum pushrod stroke limits by chamber type, and vehicles with air brakes built on or after October 20, 1994 must have automatic brake adjusters³. Automatic adjusters reduce the problem without ending it. They can wear out or malfunction, and a brake that keeps going out of adjustment can point to a worn component elsewhere in the brake assembly. Part 396 also requires that anyone responsible for brake inspection, maintenance or repair meet minimum qualifications⁴.

Tires. Part 393 bars operating on a tire with exposed ply or belt material, tread or sidewall separation, a flat or an audible leak. Front tires on a truck or tractor need at least 4/32 inch of tread depth. Other positions need 2/32 inch³. A steer tire failure at highway speed can pull a truck across lanes before the driver reacts.

Steering and suspension. Part 393 covers steering wheel lash, cracked or missing axle positioning parts, and broken or shifted leaf springs³. These failures tend to develop slowly, as handling problems a driver may learn to live with.

Lighting and conspicuity. Lamps and reflective devices must not be obscured by the load, its covering or dirt. Trailers 80 inches or wider with a gross vehicle weight rating over 10,000 pounds, built on or after December 1, 1993, must carry retroreflective sheeting, reflex reflectors or a combination of the two³. A dark or dirty trailer stopped on a shoulder at night is hard to see until a following driver is close.

Coupling devices. The fifth wheel must be securely mounted and must have a locking mechanism that prevents the halves from separating without a deliberate release³. A trailer that separates on the road leaves a loaded box with no tractor.

Cargo securement. Subpart I of Part 393 requires cargo to be contained, immobilized or secured so it does not leak, spill, blow or fall from the vehicle, and does not shift enough to affect the vehicle’s stability or maneuverability. Tiedowns must be rated to withstand set forces, including 0.8 g of forward deceleration and 0.5 g laterally³. In the LTCCS, cargo shift was coded for only 4 percent of trucks. When it was coded, it carried a relative risk of 56.3, the highest in the study¹².

What Part 396 requires

Part 396 sets out a chain of inspections, each with its own record and its own retention period⁴.

Requirement	Section	Record kept
Systematic inspection, repair and maintenance	396.3	1 year where the vehicle is housed or maintained, and 6 months after it leaves the carrier’s control
Driver vehicle inspection report	396.11	3 months
Driver review before driving	396.13	Driver signs the last report
Annual periodic inspection	396.17	Report retained 14 months

Systematic maintenance. Under 396.3, every motor carrier must “systematically inspect, repair, and maintain” every vehicle under its control, and parts must be in safe and proper operating condition at all times. Records must identify the vehicle, show the nature and due date of scheduled work, and record what was done and when⁴. The rule sets no mileage or calendar interval. The carrier sets the schedule and has to follow it.

The daily report. At the end of each day’s work, the driver must report in writing on each vehicle driven, covering at least service and parking brakes, steering, lights and reflectors, tires, horn, wipers, mirrors, coupling devices, wheels and rims, and emergency equipment. A report is required only if a defect is found or reported. Before the vehicle runs again, the carrier must repair any listed defect likely to affect safety and certify the repair, or certify that none was needed⁴.

Before the next trip. Under 396.13, the driver must be satisfied the vehicle is safe to operate, review the last inspection report, and sign it to acknowledge any required repairs were certified⁴.

The annual inspection. Every commercial motor vehicle, including each trailer in a combination, must pass a periodic inspection of the components in Appendix A to Part 396 at least once every 12 months, performed by a qualified inspector, with documentation on the vehicle⁴.

Above all of these sits 396.7: a vehicle may not be operated in a condition likely to cause a crash or breakdown⁴.

Roadside inspections and out-of-service orders

State and federal inspectors also stop trucks at scales and roadside sites, using the Commercial Vehicle Safety Alliance’s inspection procedures. A Level I inspection is the full check of driver credentials and the vehicle’s mechanical condition. Level II is a walk-around limited to what can be checked without going under the vehicle. Level V is a vehicle-only inspection⁶.

The pass-fail standard is CVSA’s North American Standard Out-of-Service Criteria, updated each year effective April 1⁵. A vehicle with an out-of-service condition cannot be operated until the defect is repaired. When FMCSA inspectors place a vehicle out of service, federal rules bar anyone from operating it or removing the out-of-service sticker until the required repairs are done, though it may be towed away by crane or hoist. The carrier must certify within 15 days that the violations were corrected⁴.

The results show where trucks fail. During CVSA’s 2026 International Roadcheck, inspectors across North America placed 10,350 vehicles out of service, 19 percent of the vehicles inspected. Brake systems were the top vehicle out-of-service violation at 3,379, or 24.3 percent of all vehicle out-of-service violations. Tires followed at 20.9 percent. A separate brake category, vehicles with 20 percent or more of their brakes defective, made up another 14.9 percent. Cargo securement came to 12.4 percent and lights to 11.9 percent⁷. CVSA says brake-related violations “continue to be one of the leading reasons vehicles are placed out of service”⁸.

Why the records matter after a crash

A defect found at roadside is a violation. A defect found after a crash raises a different question: did the carrier know, or should it have known?

The maintenance file is where that question gets answered. Investigators and litigants look for:

Daily reports listing a defect, and whether the repair was certified before the next trip.
Repeated write-ups of the same component, which can suggest a problem was patched rather than fixed.
Gaps between the carrier’s own schedule and the work actually done.
Annual inspection reports, and whether the inspector was qualified.
Prior roadside inspections and out-of-service orders on the same vehicle.
Who worked on the brakes, and whether that person met the brake inspector qualifications.

Retention periods are short. Daily inspection reports need be kept only 3 months⁴, which is why preservation requests often go out soon after a serious crash. A post-crash inspection of the truck itself, measuring pushrod stroke, lining thickness and tire condition, can confirm or contradict the paperwork. Our guide to evidence after a truck crash covers the full set of records, and our explainer on liability in commercial vehicle collisions covers how maintenance failures can bear on a carrier’s responsibility, which varies by state and by the facts. For how vehicle failures rank against driver and roadway factors, see our analysis of the leading causes of large truck crashes.

What Data Is Stored in a Commercial Truck's Electronic Control Module?

2026-10-07T00:00:00Z

After a serious crash involving a tractor-trailer, the questions that matter most are often numerical. How fast was the truck going? When did the driver come off the throttle? When did braking begin? No federal rule requires a heavy truck to carry a crash recorder, but many carry something close to one: the engine’s electronic control module, a computer built to run the engine that also keeps records for the fleet that owns it.

What that module holds depends on who made the engine, which software it runs and how the fleet configured it. What follows describes what is commonly found, how it is retrieved and how it is lost.

What the module is and why heavy trucks have one

The engine control module, usually shortened to ECM, meters fuel, manages engine timing and responds to the accelerator pedal. On many trucks it also holds the governed top speed and runs cruise control.

Engine makers added data logging for fleet customers: fuel economy, idle time, trip summaries, maintenance intervals. A NHTSA working group reported in 2002 that this data served mostly fleet management, but that such a module, though “not a dedicated crash recorder,” can act as “a surrogate Event Data Recorder,” and that the National Transportation Safety Board had used engine data in crash investigations¹.

The federal event data recorder rule, 49 CFR Part 563, covers only passenger cars and other light vehicles rated at 8,500 pounds or less, and only when they are equipped with a recorder². Heavy trucks fall outside it. No federal standard dictates which crash data a heavy-truck engine must keep, in what format or for how long. The module does touch one federal rule: an electronic logging device in a truck of model year 2000 or later must link to the engine ECM and take power status, motion status, miles and engine hours from it³.

What the records commonly include

These categories are typical, not universal. Each engine maker defines its own reports, names them differently and changes them across software generations. Some depend on settings: Detroit says that if the fleet management data page is disabled on certain controllers, trip data is not collected at all⁴.

Event records. Many modules save a short record when the truck slows faster than a set rate, as in hard braking or a collision. Cummins calls this a Sudden Deceleration Data report; Detroit modules record Hard Brake events⁵⁶. Cummins’ PowerSpec manual says the report covers time, vehicle speed, engine speed, engine load and throttle, and “will contain between 1-3 records”⁷. Engineers who tested it described second-by-second speed data⁵. The trigger rate and the length of the recording window vary by maker and module. [Verified statistic and source required: manufacturer-documented deceleration trigger (mph per second) and recording window (seconds before and after the trigger) for current Cummins, Detroit and PACCAR engine modules]

Last stop records. Detroit modules keep a Last Stop Record¹⁶, which, as the name indicates, covers the truck’s most recent stop, with vehicle speed, engine speed and accelerator pedal position logged at intervals⁸.

Trip, activity and fault data. Detroit lists trip data, monthly activity, idle time, speed and RPM reports, daily engine usage and diagnostic records among its standard outputs⁴. Fault codes⁷ can matter when a mechanical failure is in question.

Settings. The module stores its configuration, which on many engines includes a governed maximum speed⁹. PowerSpec reads a feature settings report and keeps a history of changes to those settings⁷. Regulators withdrew a proposed heavy-truck speed limiter mandate in July 2025⁹, so a governed speed remains the manufacturer’s or carrier’s choice.

Time stamps. Detroit says its controllers keep time in GMT and that “clock drift will occur no matter what”⁴. ECM times are treated as approximate until matched against another clock, such as an ELD log or a camera time stamp.

How the data is downloaded

The data is read through the truck’s diagnostic connector with an adapter and the engine maker’s software: PowerSpec and related tools for Cummins, DDEC Reports for Detroit, and equivalents for other makers⁷⁴.

The same tools can erase what they read. PowerSpec has buttons that reset trip information and inactive fault codes⁷, and the 2002 NHTSA report noted that a Detroit trip file “may be reset after it is extracted”¹. Careful practice puts imaging first: the data is captured before the truck is started, moved, repaired or road-tested; each step is documented; and the raw download file is kept with any printed report. The work calls for people trained on the specific software. Where several parties have a stake, a download can be scheduled so each can attend.

Standard methods need a working module⁶. When the crash has disabled it, researchers have shown that records can be read straight from the memory chips, recovering a Last Stop Record, two Hard Brake events and a daily engine usage log from a Detroit DDEC V⁶.

How the data gets lost

Later events. Event storage is small. A report holding one to three records can lose the crash record if the truck logs more hard decelerations during recovery, towing or road testing. Driving the truck and stopping it again can replace the last stop record that matters.

Power. Starting the engine creates new data. Detroit warns that “if power is cut or interrupted during the data-writing sequence, more than likely data will be lost”⁴, and disconnecting batteries or cutting cables to free a damaged cab can do exactly that.

Service and salvage. A shop doing routine work may clear trip data and inactive faults. A replaced or reprogrammed module, or a truck sold for salvage, can take its data with it.

Physical damage. Fire, water and impact can destroy a module. Chip-level recovery works in some cases, not all.

How ECM data differs from ELD, telematics and camera records

Source	Built to capture	Where it is kept
Engine ECM	Engine data; short event records	In the module
ELD	Driver duty status	Device and carrier system
Telematics	Location, speed, alerts	Vendor and carrier servers
Cameras	Video of road and driver	Device memory; vendor servers

ELD records. An electronic logging device enforces hours-of-service limits. It records each duty status change with date, time, location, engine hours, miles and driver identity, plus an hourly entry while the truck moves³. Location is kept to about a 1-mile radius during on-duty driving, and carriers keep the records six months³. It is a log of the driver’s day, not a second-by-second account of a crash. See What an Electronic Logging Device Records.

Telematics. Fleet units send location, speed and alerts such as harsh-braking events to a vendor’s servers, kept as long as the contract and settings allow. They may read speed from the same network as the ECM, so the two are not always independent checks.

Cameras. Forward-facing and driver-facing cameras commonly record on a loop that overwrites itself and save clips when an event sets them off. Video shows the road and the driver but not throttle position; the ECM shows throttle but not where the other vehicle was.

Speed data has limits. Heavy-truck recorders can understate speed during hard braking, when wheel slip makes the wheels turn slower than the truck moves¹⁰. A study of Detroit engines in Freightliner’s New Cascadia found some Last Stop and Hard Braking records spaced points two seconds apart while reporting one-second intervals, an anomaly the record itself does not reveal⁸.

How reconstructionists use it

ECM data gives a reconstruction a timeline: speed in the seconds before the event, when the throttle released, how quickly the truck slowed and, where reported, when the brakes came on. Engineers test that timeline against tire marks, rest positions, crush damage and the other vehicle’s recorder. When numbers and physics disagree, the gap points somewhere useful: clock error, wheel slip, a missing record or a wrong assumption about the scene. The methods are covered in How Crash Reconstruction Works.

The module cannot say where the driver was looking or what the other vehicle did. That comes from video, witnesses and the scene, which is why investigators try to secure all of it before the clocks described in Evidence After a Commercial Vehicle Crash run out.

Commercial Truck Driver Fatigue: Statistics and Safety Risks

2026-10-07T00:00:00Z

Every hours-of-service rule in federal law is a fatigue rule, and fatigue is the crash factor the national record measures worst. When federal investigators took apart nearly a thousand serious truck crashes in the early 2000s, they coded fatigue for 13 percent of the truck drivers¹. In the government’s census of fatal crashes for 2019 and 2020, police coded drivers of large trucks as asleep or fatigued 1.4 percent of the time²³. The two figures measure different things in different crashes. The distance between them is still the first thing anyone using fatigue data has to understand.

What fatigue does to a driver

Fatigue is less a single condition than three pressures that stack on top of one another.

Sleep debt. Lost sleep accumulates, and one long night does not clear it. NHTSA’s drowsy-driving guidance points adults to seven to eight hours of sleep a night⁴. A driver who starts a run short of that is carrying the deficit before the truck leaves the yard.

Circadian low points. The body’s internal clock produces two troughs in alertness every day. FMCSA advises commercial drivers to avoid driving, where they can, between midnight and 6 a.m. and between 2 p.m. and 4 p.m., when the body is naturally drowsy⁵. NHTSA reports that drowsy-driving crashes happen most often between midnight and 6 a.m. or in the late afternoon⁴. Freight schedules do not follow biology, and overnight runs put trucking work across the deepest trough.

Time on task. FMCSA’s guidance warns that drowsiness can deepen the longer a driver has been on the road, but it also reports that an FMCSA study found alertness was tied more closely to time of day than to time on task⁵. A rule that caps hours without regard to when they fall addresses only part of the problem.

All three end in the same place: the micro-sleep. NHTSA describes brief losses of consciousness lasting four or five seconds, and notes that at 55 miles per hour a vehicle covers more than 100 yards in that time⁴.

What the Large Truck Crash Causation Study found

The Large Truck Crash Causation Study (LTCCS), run by FMCSA and NHTSA, examined 967 crashes from 2001 to 2003 at 24 sites in 17 states. Each involved at least one large truck and at least one injury or death, and the sample was weighted to represent about 141,000 trucks nationally¹. Investigators interviewed drivers and witnesses, inspected the trucks and pulled carrier, police and medical records.

Fatigue was coded as an associated factor for 13.0 percent of the trucks. An associated factor is any of roughly 1,000 conditions recorded as present at the time of the crash. The code says the condition existed, not that it contributed. FMCSA’s report is blunt on the point: “None of these variables in and of themselves should be considered the cause of the crash”¹. A fatigued trucker who is struck from behind at a red light still has fatigue on the form.

Two related codes sit in the same table. Drivers were coded as under work-related pressure in 9.2 percent of cases, and as pressured to operate even though fatigued in 3.2 percent¹.

The study’s analysis brief asked a sharper question. For each factor it calculated a relative risk: how often trucks with the factor were assigned the “critical reason” for the crash, the immediate failure that made the collision unavoidable, compared with trucks without it. That is a research classification, not a finding of fault. For fatigue, the relative risk was 8.0⁶. When fatigue was coded, the truck was eight times as likely to be the vehicle assigned the “critical reason”.

A fatigued trucker who is struck from behind at a red light still has fatigue on the form.

The study also cuts against the picture of the tired trucker as the whole story. In two-vehicle crashes between a large truck and a passenger vehicle, fatigue was coded for about 7.5 percent of truck drivers and 14.7 percent of passenger vehicle drivers, roughly twice as often for the person in the car¹.

Why police crash data undercount fatigue

FARS, NHTSA’s census of fatal crashes, records driver-related factors from police reports. Among drivers of large trucks in fatal crashes, 71 of 4,949 were coded as asleep or fatigued in 2019, and 68 of 4,777 in 2020²³. That is 1.4 percent in each year.

The FARS and LTCCS figures cannot be read as a trend. One is a census of fatal crashes built from police reports. The other was a weighted sample of injury and fatal crashes worked by trained investigators two decades earlier. The gap still points where NHTSA itself points. The agency says a precise count of drowsy-driving crashes “is not yet possible,” that its figures rely on police and hospital reports, and that there is broad agreement those figures are an underestimate⁴. Across all vehicle types, NHTSA reports 644 deaths in drowsy-driving crashes in 2024⁴.

The reasons are practical:

There is no roadside test for fatigue, nothing like a breath test for alcohol.
The driver may be dead, badly hurt, or unwilling to say how long he or she had been awake.
An officer sees the result (no braking before impact, a slow drift across a lane) but not the state of the person at the wheel.
The evidence that would support the code, such as hours on duty in the days before, sits in records the officer does not have at the scene.

In 2019, 4.0 percent of large-truck drivers in single-vehicle fatal crashes were coded asleep or fatigued, against 0.8 percent in multiple-vehicle crashes². One plausible reading is that fatigue is easier to identify when no other driver’s actions compete for the explanation. Either way, treat police-coded fatigue as a floor. Our field guide to U.S. crash data covers how these datasets are built.

Sleep apnea and the medical certificate

Obstructive sleep apnea is a disorder in which the upper airway repeatedly narrows or closes during sleep, interrupting breathing and breaking up sleep, often without the sleeper knowing. The result can be heavy daytime sleepiness in someone who believes he or she slept a full night. [Verified statistic and source required: estimated prevalence of moderate-to-severe obstructive sleep apnea among U.S. commercial motor vehicle drivers, from FMCSA Medical Review Board materials or a peer-reviewed study]

Interstate commercial drivers must generally pass a physical given by a medical examiner listed on FMCSA’s National Registry of Certified Medical Examiners and be re-examined at least every 24 months (49 CFR 391.43 and 391.45)⁷. The physical standard that covers apnea is a general one. Section 391.41(b)(5) disqualifies a driver with a respiratory dysfunction likely to interfere with the ability to control the vehicle safely. The regulation does not mention sleep apnea.

Rulemaking to change that started and stopped. In March 2016, FMCSA and the Federal Railroad Administration published an advance notice of proposed rulemaking on moderate-to-severe obstructive sleep apnea among drivers and rail workers in safety-sensitive jobs. In August 2017 the agencies withdrew it, saying current safety programs and FRA’s fatigue risk management rulemaking were the appropriate ways to address the issue⁸⁹.

What remains is guidance. FMCSA’s Medical Examiner’s Handbook, issued in final form in January 2024, states that the regulations do not require examiners to screen drivers for sleep apnea or to refer them for testing, and FMCSA says it “has not adopted requirements regarding OSA screening, testing, or treatment”¹⁰. The handbook leaves the call to the examiner. Whether a driver with untreated apnea is identified depends heavily on who performs the exam.

Schedule pressure, detention and parking

Fatigue is also an operations problem. Under 49 CFR 395.2, on-duty time includes time spent at a shipper’s property waiting to be dispatched and time attending a truck while it is loaded or unloaded¹¹. For property carriers, the 14-hour window keeps running through all of it, and the next appointment rarely moves to match. Our explainer on hours-of-service rules walks through how the clocks interact on a day like that.

The Department of Transportation’s Office of Inspector General put a number on the risk in 2018. Using 2013 data, it found that “a 15-minute increase in average dwell time increases expected average crash rates by 6.2 percent,” and estimated that detention was associated with $1.1 billion to $1.3 billion a year in lost earnings for truckload drivers¹². The same report said accurate industrywide detention data do not exist.

Then comes the question of where to sleep. Jason’s Law is named for Jason Rivenburg, a truck driver who in March 2009 arrived near a South Carolina delivery before the receiver was open, parked at an abandoned gas station, and was attacked and murdered while he slept¹³. The law, enacted as part of MAP-21, required a survey of whether each state could offer adequate truck parking. FHWA’s 2015 results documented more than 300,000 truck parking spaces. More than 75 percent of truck drivers reported regularly having problems finding safe parking when they needed rest, 90 percent reported struggling at night, and almost half of state transportation departments reported unofficial or illegal truck parking on freeway ramps and shoulders¹⁴.

The shortage turns directly into fatigue risk. A driver who knows the lots fill by evening can stop early to claim a space, giving up hours and pay, or push on toward a distant lot and arrive tired.

What the records show, and what they miss

No device measures fatigue. The hours-of-service record is the nearest proxy: when the driver came on duty, how long he or she drove, and when breaks and sleeper-berth periods fell. Bills of lading and dispatch records can show where detention ate the day. None of it shows whether off-duty time was spent asleep. Our brief on what an electronic logging device records sets out what that data contains, and our analysis of the leading causes of large truck crashes places fatigue alongside the other factors the federal study coded.

For a carrier reviewing a crash, the useful question is not only whether the driver was within the rules. It is what the days before looked like: when the driver slept, where the truck sat overnight, and how long the last stop really took.

Texas Commercial Truck Crash Statistics

2026-10-07T00:00:00Z

Texas police reported 38,533 crashes involving a commercial motor vehicle in 2025. Those crashes killed 528 people and left 1,611 with suspected serious injuries¹. The 528 deaths were 14 percent of the 3,769 traffic deaths TxDOT recorded statewide that year¹¹⁴. The figures come from the state’s crash records system, and they count crashes in which the investigating officer marked a commercial motor vehicle as involved. That is a different measure from the federal “large truck” counts, and the difference matters for any comparison.

The sources

TxDOT Crash Records Information System (CRIS). TxDOT collects the crash reports Texas officers file and keeps a statewide database of reportable crashes. It says each year’s summary reports are published by June of the following year⁷. One of those reports breaks out commercial motor vehicle crashes by county and severity¹. The public CRIS Query tool lets anyone filter and export publicly available crash data⁷⁸. TxDOT keeps crash records for the previous 10 full calendar years plus the current year¹⁶.

NHTSA Fatality Analysis Reporting System (FARS). The national census of fatal crashes. NHTSA’s annual large-truck fact sheet carries a state table built from it⁹.

FMCSA Motor Carrier Management Information System (MCMIS). Crash reports on trucks and buses that states send to FMCSA, published through Analysis & Information (A&I) Online. A&I treats MCMIS crash data as preliminary for 22 months¹⁰.

The differences among the three are covered in the field guide to U.S. crash data.

Statewide, by year

Year	CMV crashes	Fatal crashes / deaths	Suspected serious injuries
2025	38,533	469 / 528	1,611
2024	39,393	546 / 608	1,601
2023	38,928	549 / 621	1,687
2022	38,658	603 / 706	1,645
2021	38,176	631 / 706	1,708
2020	32,585	511 / 580	1,245

Sources: TxDOT, Commercial Motor Vehicle (CMV) Involved Crashes and Injuries by County, 2020 to 2025¹²³⁴⁵⁶. Deaths are all people killed in those crashes, not only truck occupants. Serious injuries are people, not crashes.

The total includes crashes of every severity. In 2025, 27,587 of the 38,533 crashes were coded as non-injury crashes¹.

Counties with the most CMV crashes

County	CMV crashes, 2025	Fatal crashes	Deaths
Harris	5,913	41	43
Dallas	3,778	33	37
Bexar	2,581	12	16
Tarrant	2,183	15	16
El Paso	1,014	7	7
Denton	948	5	5
Webb	746	4	4
Collin	684	7	7
Montgomery	674	1	1
Travis	648	7	11

Source: TxDOT, CMV Involved Crashes and Injuries by County, 2025¹.

These ten counties accounted for 19,169 of the state’s 38,533 CMV crashes in 2025, about half. Harris, Dallas, Bexar and Tarrant ranked first through fourth, in that order, in every year from 2020 to 2025¹²³⁴⁵⁶. These are raw counts, not rates per mile traveled or per truck registered.

By road class

Template for a CRIS Query pull of CMV-involved crashes by road class, for the most recent complete year. The rows follow the road classes in TxDOT’s public CRIS extract specification¹⁷, leaving out toll bridges and non-trafficway locations.

Road class	CMV crashes	Fatal CMV crashes
Interstate	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
U.S. and state highways	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
Farm to market	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
County road	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
City street	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
Tollway	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
Other roads	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]

By time of day

Template for the same pull, grouped by the crash time on the CR-3.

Crash time	CMV crashes	Fatal CMV crashes
Midnight to 3:59 a.m.	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
4 a.m. to 7:59 a.m.	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
8 a.m. to 11:59 a.m.	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
Noon to 3:59 p.m.	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
4 p.m. to 7:59 p.m.	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]
8 p.m. to 11:59 p.m.	[Verified statistic and source required: CRIS Query, CMV crashes]	[Verified statistic and source required: CRIS Query, fatal CMV crashes]

For the factors police record in truck crashes nationally, and what those codes can and cannot show, see leading causes of large truck crashes.

One state, three death counts

The three systems give different answers for the same state and year.

Source	What it counts	Texas deaths, 2024
TxDOT CRIS	People killed in crashes where police marked a CMV	608
NHTSA FARS	People killed in crashes involving a large truck	720
FMCSA MCMIS (A&I)	Fatalities in reported crashes involving large trucks and buses	[Verified statistic and source required: FMCSA A&I Crash Statistics, Texas, 2024, MCMIS fatalities]

Sources: TxDOT 2024 CMV report²; NHTSA, Large Trucks: 2024 Data, Table 7⁹; FMCSA A&I¹⁰.

None of these numbers is wrong. They define the vehicle differently, as the next section shows. The FARS figure for 2024 comes from NHTSA’s Annual Report File and can change when the Final File is released⁹.

Methods

What Texas counts as a commercial motor vehicle crash

TxDOT defines a commercial motor vehicle crash as one the investigating officer identified as involving a CMV by selecting the “CMV” indicator on the CR-3¹³. The police instruction manual tells officers to select it when the crash involved or was related to a commercial motor vehicle or other large vehicle, and defines a CMV as one ordinarily used in interstate or intrastate commerce that weighs 10,000 pounds or more, carries hazardous material, or has a capacity of nine or more people. It is required for buses, school buses and truck tractors¹². The CMV section’s weight identifier is a gross vehicle weight rating or registered gross weight of 10,001 pounds or more, for a single vehicle or a combination¹².

NHTSA’s FARS-based large-truck tables count any medium or heavy truck with a gross vehicle weight rating over 10,000 pounds, excluding buses and motor homes, whether used commercially or not⁹. FMCSA’s A&I counts commercial trucks over 10,000 pounds, any vehicle designed to carry nine or more people, and any vehicle displaying a hazardous materials placard¹¹. So the TxDOT count includes buses and FARS does not, while FARS includes heavy trucks not used in commerce. The federal definitions are in the reader’s map to the FMCSRs.

What counts as a reportable crash

TxDOT defines a reportable crash as one involving a motor vehicle in transport, on or originating on a trafficway, that results in injury or death or apparent damage of $1,000 to any one person’s property¹³. TxDOT’s police manual cites Texas Transportation Code § 550.062 for the rule that an officer who investigates a crash with injury or death must send the report to TxDOT within 10 days, and tells officers to submit any investigated crash with $1,000 or more in damage to one person’s property as well¹². A fatality is a death within 30 days of the crash¹³.

Serious injuries

A suspected serious injury, called an incapacitating injury before the 2010 reports, is any nonfatal injury that keeps the person from walking, driving or normally continuing the activities they could do before the crash¹³. It is recorded by the officer on the crash report, not by a physician.

Known limits

Officer coding. Whether a crash counts as a CMV crash depends on the box the officer checks. A qualifying vehicle the officer does not flag is not counted.
Counts change. Each report states the date its data were processed. Statewide traffic deaths for 2024 were reported as 4,150 in TxDOT’s 2024 summary and as 4,159 a year later¹⁵¹⁴. The CMV figures here can move the same way.
Unreported crashes. CRIS is built from officers’ reports. Crashes no officer investigated, and private-property crashes an agency chooses not to submit, are not in it⁷¹².
Counts, not rates. TxDOT’s CMV report gives no truck mileage by county, so these tables cannot say where trucks are more dangerous per mile.
Form changes. TxDOT has used several versions of the CR-3 within its 10-year retention window¹⁶. Compare fields across years with care.

How to cite this page: BTT Road & Legal, “Texas Commercial Truck Crash Statistics,” October 7, 2026, https://bttlaw.com/research/texas-commercial-truck-crash-statistics/. For any figure, cite the TxDOT, NHTSA or FMCSA document listed in the sources.

Pedestrians, Cyclists and the Shape of the Road

2026-10-07T00:00:00Z

A driver and a pedestrian can make the same mistake at the same moment: one misjudges a gap, the other steps out a beat too early. Only one of them has a steel frame, airbags and a seat belt. The other has skin. That asymmetry is why traffic engineers increasingly treat the street itself as the safety equipment for people on foot and on bikes.

The toll is large. NHTSA counted 7,080 pedestrians and 1,103 cyclists killed in U.S. traffic crashes in 2024.¹² The Safe System Approach adopted by the U.S. Department of Transportation starts from the premise behind that asymmetry: “Human bodies have physical limits for tolerating crash forces before death or serious injury occurs.”³ Three features of the road decide how often those limits are tested.

Speed sets the stakes

The physics is unforgiving. A moving vehicle’s kinetic energy rises with the square of its speed, so a car at 40 mph carries four times the energy of the same car at 20 mph. When a car strikes a person, the body absorbs much of that energy.

Speed also shrinks the chance to avoid a crash at all. At 30 mph a car covers 44 feet every second; at 45 mph, 66 feet. Distance covered while the driver is still reacting grows in step with speed, and braking distance grows with its square. A driver who would stop short of a crosswalk at one speed may still be traveling fast when reaching it at a higher one.

How sharply the risk climbs has been measured. A 2011 AAA Foundation for Traffic Safety study by Brian Tefft used federal data on U.S. crashes from 1994 to 1998 in which a pedestrian was struck by a forward-moving car, light truck, van or SUV, adjusted to represent pedestrians struck in 2007 to 2009. It estimated that a struck pedestrian’s average risk of death reaches 10 percent at an impact speed of 23 mph, 25 percent at 32 mph, 50 percent at 42 mph, 75 percent at 50 mph and 90 percent at 58 mph.¹⁴ The average risk of severe injury reaches 50 percent at 31 mph. Older pedestrians face much higher risk at any given speed.¹⁴ These are impact speeds, which can be well below the speed a car was traveling before the driver braked. A street designed for higher speeds asks the human body to absorb forces it was not built for.

Wide roads and long crossings

Most pedestrian deaths happen away from intersections. In 2024, 73 percent of pedestrian fatalities occurred at locations that were not intersections, and 84 percent occurred in urban areas.¹ For cyclists, 30 percent of 2024 deaths occurred at intersections, and 81 percent were in urban areas.²

The multilane arterial, a wide road with four or more travel lanes, commercial driveways and signals spaced far apart, concentrates several risks. Speeds are higher. The walk to a signalized crossing can be long, so people cross where they are. Each extra lane adds time in the road and another stream of traffic to judge.

Width also creates a specific hazard. FHWA’s crash-type manual describes the “multiple threat” crash, in which a pedestrian entering the road at midblock in front of stopped or standing traffic is struck.⁴ On a road with more than one lane in each direction, a vehicle stopped in one lane can hide the pedestrian from a driver approaching in the next.

Darkness

Most pedestrian and cyclist deaths happen after dark. In 2024, 76 percent of pedestrian fatalities occurred in the dark, compared with 20 percent in daylight and 2 percent each at dawn and dusk.¹ For cyclists, 52 percent died in darkness and 44 percent in daylight.²

FHWA frames the broader nighttime picture this way: fatal crashes in daylight and in darkness are about equal in number, but “only 25 percent of vehicle miles traveled (VMT) occur at night,” and the nighttime fatality rate is three times the daytime rate.⁵ At night, drivers have less time to see a pedestrian. Darkness also overlaps with other risks, such as fatigue and impairment, that these counts do not separate out.

People on bicycles share the road with vehicles many times their weight. In 2024, 52 percent of cyclist deaths occurred in the dark. Photo: Tima Miroshnichenko / Pexels

The Federal Highway Administration maintains a list of Proven Safety Countermeasures, which it describes as “a collection of countermeasures and strategies effective in reducing roadway fatalities and serious injuries.”⁶ State and local agencies use it as a menu when they plan projects. Several items target the risks above.

Leading pedestrian intervals. The walk signal comes on 3 to 7 seconds before drivers get a green.⁷ Pedestrians step into the crosswalk first, where turning drivers are more likely to see them. FHWA says it lets pedestrians “better establish their presence in the crosswalk before vehicles have priority to turn right or left.”⁷

Medians and pedestrian refuge islands. A raised island in the middle of the road lets people cross one direction of traffic at a time.⁸ On a wide arterial, that turns one long, exposed crossing into two shorter ones.

Pedestrian hybrid beacons. These signals stay dark until a pedestrian pushes the button, then run a yellow-to-red sequence that stops traffic for the crossing. FHWA calls them “very effective at locations where three or more lanes will be crossed.”⁹

Rectangular rapid flashing beacons. Pedestrian-activated lights mounted with the crossing sign at uncontrolled, marked crosswalks. When activated, they “flash with an alternating high frequency” to catch drivers’ attention.¹⁰

Lighting. FHWA lists lighting as a crosscutting countermeasure, aimed squarely at the nighttime risk described above.⁵

Road diets. A road diet typically converts a four-lane undivided road into two through lanes and a center two-way left-turn lane. FHWA’s guidance lists “fewer lanes for pedestrians to cross” and room for refuge islands and bike lanes among the benefits.¹¹

How this fits the Safe System Approach

Each of these tools follows the same reasoning. Instead of relying on every driver and every pedestrian to be perfect, it builds in a margin. A refuge island leaves room for a pedestrian who misjudged the far lanes. A leading interval gives a turning driver who was not looking closely an earlier, clearer view. Lower speeds give everyone more time and leave less energy to absorb when things still go wrong.

That is the Safe System Approach in practical form. USDOT’s version accepts that “people will inevitably make mistakes” and calls for road environments designed “to mitigate human mistakes and account for injury tolerances.”³ Its Safer Speeds objective calls for “context-appropriate roadway design” and “appropriate speed-limit setting.”³

The approach also reframes a familiar statistic. NHTSA’s often-quoted finding that the “critical reason” was assigned to a driver in about 94 percent of sampled crashes is sometimes read as a reason to focus only on drivers. The Safe System view reads the same fact the other way: if mistakes are constant, the road has to absorb them. Our explainer on what share of crashes involve human error traces that argument from the original data.

What Percentage of Car Accidents Are Caused by Human Error?

2026-10-07T00:00:00Z

Ninety-four percent. That is the number behind most claims that human error causes nearly all crashes, and it comes from the National Highway Traffic Safety Administration. In a national survey of crashes investigated at the scene from 2005 to 2007, NHTSA researchers assigned the “critical reason” for the crash to a driver in an estimated 94 percent of cases, with a 95 percent confidence margin of plus or minus 2.2 percentage points.¹

The number answers a narrower question than the one it is usually asked to answer. The “critical reason” is the immediate reason for the last event before impact, which NHTSA describes as often the last failure in the causal chain. NHTSA states that it “is not intended to be interpreted as the cause of the crash nor as the assignment of the fault to the driver, vehicle, or environment.”¹ So the accurate short answer is this: in about 94 percent of the crashes NHTSA sampled, researchers traced the final failure before impact to a driver. Whether human error caused those crashes, in the everyday sense of the word, is a question the survey was not built to settle.

Where the number comes from

Congress authorized the National Motor Vehicle Crash Causation Survey in the 2005 SAFETEA-LU highway law, and NHTSA’s National Center for Statistics and Analysis ran it from July 3, 2005, to December 31, 2007.¹ Unlike databases built from police reports after the fact, the survey sent researchers to crash scenes while police and vehicles were still there. They interviewed drivers, passengers and witnesses, assessed vehicles and roadways, and recorded at least 600 data elements per crash.²

Not every crash qualified. NHTSA’s report to Congress lists the rules:²

The crash happened between 6 a.m. and midnight.
Emergency medical services were dispatched to the scene.
Police were at the scene when the researcher arrived, and a completed police report was available.
At least one of the first three vehicles involved was a light passenger vehicle that was towed, or would be towed, because of damage.

Those rules shaped the sample. It leans toward crashes bad enough to bring an ambulance and a tow truck. It leaves out the hours between midnight and 6 a.m. And because it requires a light passenger vehicle, crashes involving only motorcycles or heavy trucks fall outside it.

What “critical reason” means

NHTSA coded each crash in layers.¹ First came the vehicle’s movement just before trouble began. Next came the decisive event before the crash, which NHTSA defines as the circumstance that led to the vehicle’s first impact: a car drifting from its lane, say, or turning across another car’s path. The “critical reason” is the immediate reason for that event. Last came associated factors: conditions present that were likely to add to the probability of a crash.

Researchers normally assigned one “critical reason” per crash, to a driver, a vehicle or the environment.¹ That design puts a single label on events that often have several contributors. Picture a driver who glances at a phone and drifts across the center line of a narrow, unlit two-lane road. The drift is the event. The glance is a recognition error, so the “critical reason” goes to the driver. The road’s width, the missing rumble strip and the posted speed may be noted elsewhere in the file. They do not change the label.

In NHTSA's survey, researchers normally assigned one 'critical reason' per crash. In an estimated 94 percent of crashes, it went to a driver. Photo: Sindre Fs / Pexels

The driver errors, broken down

Among the estimated 2,046,000 crashes in which the “critical reason” was assigned to a driver, NHTSA sorted the errors into five groups.¹

Error type	Share of driver-assigned crashes	What NHTSA includes
Recognition error	41% (±2.2)	Inattention, internal and external distraction, inadequate surveillance
Decision error	33% (±3.7)	Too fast for conditions or a curve, false assumption of others’ actions, illegal maneuver, misjudged gap or speed
Performance error	11% (±2.7)	Overcompensation, poor directional control
Non-performance error	7% (±1.0)	Sleep was the most common
Other	8% (±1.9)	Other driver errors

Margins are 95 percent confidence limits in percentage points. Shares are of driver-assigned crashes, not of all crashes, and NHTSA computed them from unrounded estimates. Source: NHTSA, DOT HS 812 115, Table 2.

Two details trip up careful readers. The note’s summary paragraph gives the recognition-error margin as ±2.1, while Table 2 gives ±2.2. And NHTSA’s 2008 report to Congress, drawing on the same survey, put decision errors at about 34 percent and performance errors at 10 percent.² The 2015 note’s figures, 33 and 11 percent, are the ones in circulation today.

Recognition errors lead the list, and that is where distraction sits. A driver who looks toward oncoming traffic without registering a motorcycle, or who is reading a screen when the car ahead stops, belongs in this group. We look at what that means for riders in Distracted Driving and Motorcycle Crashes.

What the number does not mean

NHTSA’s own note is blunt. Of the crashes assigned to drivers, it says “in none of these cases was the assignment intended to blame the driver for causing the crash.”¹ Four limits follow from the survey’s design.

It is not a cause. The label marks the last link in a chain. Lane width, sight lines, speed limits and vehicle design sit earlier in that chain and are not what the 94 percent measures.

It likely undercounts vehicle problems. NMVCCS researchers did not perform detailed vehicle inspections. NHTSA says vehicle-related reasons were mainly inferred from external visual checks of parts such as tires and brakes, so the 2 percent vehicle share may miss problems that cannot be seen from outside.¹

It describes a sample, not all crashes. The survey covered tow-away crashes involving light passenger vehicles, with EMS dispatched, between 6 a.m. and midnight. It was not designed as a study of fatal crashes, and it does not define a category of “serious crashes.”²

It is old. The survey ended in December 2007, the year the first iPhone went on sale. Phones, vehicle technology and traffic deaths have all changed since.

The NTSB chair’s objection

In January 2022, with traffic deaths rising, National Transportation Safety Board Chair Jennifer Homendy told the Associated Press the statistic was misleading and that the Department of Transportation should stop using it.³ At the time, according to the AP, NHTSA’s website said “94% of serious crashes are due to human error” in a section about automated vehicles.

“That has to change,” Homendy said. “It’s dangerous.” She added: “You can’t simultaneously say we’re focused on a ‘safe system’ approach … and have a 94% number out there, which is not accurate.”³ NHTSA responded that it would update the wording on its website “to address that characterization of the data as well as provide additional information.”³

How truck crash research compares

The Federal Motor Carrier Safety Administration used the same “critical reason” concept in its Large Truck Crash Causation Study. That study examined 967 crashes from 2001 to 2003 at 24 sites in 17 states, each involving a large truck and at least one death or injury. Its 1,127 trucks were weighted to represent about 141,000 nationally.⁴

The results read differently from the passenger-vehicle survey:

The truck was assigned the “critical reason” in 55 percent of the crashes studied.
In two-vehicle crashes between a large truck and a passenger vehicle, the passenger vehicle was assigned the “critical reason” in 56 percent and the truck in 44 percent.
When the truck was assigned the “critical reason,” it went to the truck driver in 87.2 percent of cases, the truck itself in 10.1 percent, the environment in 2.3 percent and unknown in 0.3 percent.⁴

Two cautions apply before setting these beside the passenger-vehicle survey. The 10.1 percent vehicle share is a share of truck-assigned crashes, while NMVCCS’s 2 percent is a share of all crashes in its sample. And the two studies drew different samples in different years with different methods. Neither gap is a measured difference between cars and trucks.

FMCSA was explicit about the label’s limits: “Identification of a single critical reason merely begins the process of explaining why a crash occurred.”⁴ The study also coded associated factors, such as brake problems and fatigue, as present or absent, without judging whether each one contributed. Our breakdown of the leading causes of large truck crashes walks through those factors and what they can and cannot show.

The systems view

In January 2022, USDOT published its National Roadway Safety Strategy and adopted the Safe System Approach as the frame for its road safety work.⁵ The approach starts from the same observation as the 94 percent figure, that people make mistakes, and draws a different conclusion from the one the number is often used to support. Instead of treating error as the thing to eliminate, it treats error as a given and asks how roads, vehicles and speeds can be arranged so that mistakes are survivable.

The strategy lists six principles. Two carry most of the weight here:

Humans make mistakes. “People will inevitably make mistakes and decisions that can lead or contribute to crashes, but the transportation system can be designed and operated to accommodate certain types and levels of human mistakes, and avoid death and serious injuries when a crash occurs.”⁶
Humans are vulnerable. “Human bodies have physical limits for tolerating crash forces before death or serious injury occurs.”⁶

The others hold that deaths and serious injuries are unacceptable, that responsibility is shared, that safety work should be proactive, and that the system needs redundancy so a single failure does not decide the outcome. The strategy organizes its work around five objectives: safer people, safer roads, safer vehicles, safer speeds and post-crash care.⁵

Read this way, the 94 percent figure describes a design problem more than a verdict on drivers. If a driver is the last link in nearly every crash chain, the earlier links (lane width, crossing distance, speed, vehicle structure, emergency response) are where a crash can still be made survivable. That logic runs through the countermeasures covered in Pedestrians, Cyclists and the Shape of the Road.

One note for readers following the links: the department’s NRSS web page now summarizes the strategy’s priorities as safer people, safer roads and safer vehicles.⁷ The January 2022 strategy document remains the source for the full Safe System framework.⁵

How to cite this figure accurately

For reporters, researchers and safety writers, a short checklist:

Name the source. NHTSA, Traffic Safety Facts Crash•Stats, DOT HS 812 115, February 2015, using National Motor Vehicle Crash Causation Survey data.
Use NHTSA’s term. Write “critical reason,” not “cause,” “fault” or “blame.”
Give the period and scope. Crashes from 2005 to 2007, investigated at the scene, involving a towed light passenger vehicle with EMS dispatched.
Include the margin when space allows: 94 percent, plus or minus 2.2 percentage points.
Avoid three common rewrites. “94% of crashes are caused by human error,” “94% of serious crashes are due to human error” and “drivers are at fault in 94% of crashes” all claim more than NHTSA measured.
Use current data for current questions. The survey describes crashes from nearly two decades ago. For today’s fatality counts and trends, start with FARS and the other federal data sets in our field guide to U.S. crash data.

How Crash Reconstruction Works

2026-10-07T00:00:00Z

A crash lasts a fraction of a second, but it leaves records: marks on the pavement, bent metal, where the vehicles came to rest and, increasingly, data stored in the vehicles. Crash reconstruction reads those records back into a sequence of events. How fast was each vehicle going, where did they meet, and who could have done what, and when?

The answers are estimates. A good reconstruction reports ranges, names its assumptions and tests one method against another.

The physics

Conservation of momentum

In a collision, the vehicles push on each other with equal and opposite force for the same brief moment, so their combined momentum (mass times velocity, with direction) is about the same just after impact as just before. Knowing each vehicle’s mass, its direction of travel and its speed and direction just after separation, a reconstructionist can solve for the speeds before impact.

Post-impact speeds usually come from how far each vehicle traveled to rest and the friction it met on the way. Directions come from the scene diagram. Small errors in angles can produce large errors in the result, especially in shallow-angle collisions.

Crush energy

Damaged metal absorbed energy. Reconstructionists measure crush depth at several points across the damage and combine those measurements with stiffness values for the vehicle type, derived from crash tests, to estimate the energy absorbed and the vehicle’s change in velocity. Crush analysis is often run as a cross-check on momentum.

Skid to stop

When a vehicle slides to a stop, its kinetic energy is spent as friction over the slide. Setting the two equal and converting to miles per hour and feet gives the familiar formula:

S = √(30 × d × f)

S is the speed at the start of the slide, in miles per hour.
d is the slide distance, in feet.
f is the drag factor: the deceleration the tires and surface produced, as a fraction of gravity. It is measured at the scene with test skids or a drag sled, or taken from published ranges, and adjusted for grade.
30 is a rounded constant from the unit conversion (2 × 32.2 ft/s², divided by the square of 1.467 ft/s per mph, is about 29.9).

A car that left 100 feet of marks on a surface tested at 0.70 gives √(30 × 100 × 0.70), or √2,100: about 46 mph.

That figure is a minimum. It counts only energy spent along the measured marks, not braking before the marks began or any speed left over when the vehicle struck something. Antilock brakes keep the wheels turning and may leave faint marks or none. Heavy trucks need their own analysis: air brakes take a moment to apply and axles do not all brake alike, so a drag factor measured with a car does not transfer to a loaded tractor-trailer.

The data and the measurements

Event data recorders

Federal rules do not require passenger vehicles to have an event data recorder. Under 49 CFR Part 563, recorders that are installed in passenger cars and in light trucks, vans and buses rated at 8,500 pounds or less, built on or after September 1, 2012, must meet uniform standards¹.

Part 563 defines an event as a crash that produces a change in velocity of at least 8 km/h (about 5 mph) within 150 milliseconds, or that deploys a non-reversible restraint such as an air bag¹. The recorder must keep the change in velocity during the crash; vehicle speed, accelerator position and service brake status in the seconds before; and driver seat belt status, air bag warning lamp status, deployment times and ignition cycle counts¹. The pre-crash window is now 5 seconds at 2 samples per second. A 2024 amendment extends it to 20 seconds at 10 samples per second², phasing in, as revised in 2026, from vehicles built on or after September 1, 2028 to all covered vehicles built on or after September 1, 2031, with later dates for small-volume and multi-stage manufacturers³¹.

Air bag deployment records must be locked against overwriting; other event records may be replaced by later events. Manufacturers must make a retrieval tool commercially available¹.

Heavy trucks fall outside Part 563. Their engine control modules often keep event and last stop records under rules each engine maker sets. See What Data Is Stored in a Commercial Truck’s Electronic Control Module?

Mapping the scene

Calculations are only as good as the measurements behind them.

Total stations. A surveying instrument measures angle and distance to a prism held on each point of interest: the ends of a tire mark, a gouge, a rest position. It is precise, but it records only the points someone chose.
Laser scanning. A 3D scanner records millions of points, capturing surfaces no one thought to measure at the time. It sees only what is in its line of sight, so a scene usually needs several setups.
Photogrammetry. Measurements are extracted from photographs, including drone imagery. It can recover positions from police or bystander photos taken before the scene was cleared, with accuracy that depends on image quality and known reference distances in the frame.

Simulation

Simulation software models vehicle motion from mass, tire properties, steering, braking and initial speeds, and shows whether a proposed sequence produces the evidence that was found. It tests a hypothesis rather than supplying one, and more than one set of inputs can often match the same marks and rest positions.

Where each method runs out

Momentum weakens when one vehicle far outweighs the other. A loaded tractor-trailer’s velocity barely changes when it strikes a car, so small errors in the car’s measurements swamp any estimate of the truck’s speed.

Crush analysis depends on stiffness data that exists mainly for passenger vehicles in tested configurations. Underride crashes, side impacts and truck structures are poorly covered.

Skid formulas give a floor, not a figure, and lean on a drag factor that can vary along the path.

Vehicle data reports what the vehicle’s own designated speed source indicated¹. Tests on heavy trucks found recorded speed runs low during hard braking, when the wheels slip⁴. Clocks drift, and records can be overwritten.

Scene mapping cannot recover marks swept away before anyone measured or photographed them.

Simulation inherits every error in its inputs.

The strongest reconstructions use several methods and explain where they agree and where they do not.

Hours-of-Service Rules Explained

2026-10-07T00:00:00Z

A property-carrying truck driver in interstate commerce works under three federal clocks at once: an 11-hour limit on driving, a 14-hour window that caps the workday, and a weekly ceiling of 60 or 70 hours on duty. A fourth rule requires a 30-minute break after 8 hours of driving. The rules sit in 49 CFR Part 395¹. What makes them hard is how the clocks interact, so this explainer sets out each limit, then follows a hypothetical driver through a day.

Who the rules cover

The rules apply to drivers of commercial motor vehicles in interstate commerce. FMCSA describes a commercial motor vehicle, for these purposes, as one used in business that weighs or is rated at 10,001 pounds or more, is designed or used to carry 16 or more passengers without compensation or 9 or more for compensation, or carries placarded hazardous materials⁴. That reaches well beyond tractor-trailers to box trucks and service vehicles working interstate routes.

The limits side by side

The rules split by what the vehicle carries¹².

Limit	Property-carrying	Passenger-carrying
Off-duty time before driving	10 consecutive hours	8 consecutive hours
Driving limit	11 hours	10 hours
On-duty limit for driving	No driving after the 14th hour after coming on duty	No driving after 15 hours on duty
Off-duty time and the window	Does not extend the 14 hours	Not counted in the 15 hours
Rest break	30 minutes after 8 cumulative hours of driving	No break rule
Weekly limit	60 hours in 7 days or 70 in 8	60 hours in 7 days or 70 in 8
Weekly restart	34 or more consecutive hours off	No restart provision

The columns differ in structure, not only in numbers. A passenger driver’s long lunch off duty does not count toward the 15 hours. A property driver’s 14-hour window runs from the moment he or she comes on duty, and off-duty time inside it does not stop the clock².

One driver’s day, hour by hour

This is a hypothetical, built to show the mechanics. The driver, carrier and times are invented, and no sleeper berth or exception is used.

The driver hauls dry van freight for a carrier that runs seven days a week, so the 70-hours-in-8-days limit applies. He has had 10 consecutive hours off and starts the day with 40 hours already used in the 8-day period.

5:00 a.m. Comes on duty at the terminal. Pre-trip inspection and paperwork are on-duty, not driving. The 14-hour window opens now and closes at 7:00 p.m. no matter what happens in between.
5:30 a.m. Starts driving, with nothing longer than a few minutes’ stop all morning.
1:30 p.m. He has driven 8 hours without a 30-minute interruption. He may not get back behind the wheel until he takes one¹.
1:30 to 2:00 p.m. Lunch, logged off duty. Off-duty time does not pause the 14-hour window. The window still closes at 7:00 p.m.
2:00 p.m. Back on the road with 3 hours left under the 11-hour limit and 5 hours left in the window.
3:00 p.m. Arrives at the receiver. Driving total: 9 hours.
3:00 to 4:30 p.m. Waits while the trailer is unloaded. Under 49 CFR 395.2, time attending a vehicle being unloaded is on-duty time¹. The window keeps running. (Had this wait come before the 8-hour mark, it would have satisfied the break. Since the 2020 rule, any 30 consecutive minutes of non-driving time counts, on duty or off³.)
4:30 p.m. Released empty and dispatched toward the next pickup. He has 2 hours of driving left and 2.5 hours left in the window.
6:30 p.m. Driving total reaches 11 hours. The 11-hour limit stops the truck with 30 minutes still on the window. He pulls into a truck stop and goes off duty.
6:30 p.m. onward. He needs 10 consecutive hours off before his next shift behind the wheel. The day added 13 on-duty hours to his 8-day total, bringing it to 53 of 70.

Change one fact and a different clock decides. Had the receiver held him until 6:30 p.m., he would have had only 30 minutes before the window closed at 7:00, and the 14-hour limit would have ended his day with 1.5 hours of driving unused. Had his carrier not run every day, the 60-hour limit would apply. Starting the day at 50 of 60 hours, he would have hit the weekly ceiling at 3:30 p.m., on the receiver’s dock, with time left on both daily clocks. He could finish the unload but could not pull away.

The weekly limit and the 34-hour restart

The weekly limit is a rolling total of on-duty hours, not driving hours. A driver whose carrier does not operate every day is barred from driving after 60 hours on duty in 7 consecutive days. If the carrier runs every day, the cap is 70 hours in 8 days¹. Each day, the oldest day drops off and the newest is added.

The restart wipes the slate. Any 7- or 8-day period may end with the start of an off-duty period of 34 or more consecutive hours, and the count begins again at zero¹.

The sleeper berth split

A property-carrying driver with a sleeper berth may split the required 10 hours off. Under 49 CFR 395.1(g), one period must be at least 7 consecutive hours in the sleeper berth and the other at least 2 consecutive hours, off duty or in the berth. Together they must total at least 10 hours: 7 and 3, or 8 and 2¹.

Two rules make the split useful. Neither qualifying period counts against the 14-hour window, and the 11-hour and 14-hour limits are recalculated from the end of the first of the two periods¹³. A driver facing a long wait who is relieved from duty or can rest in the berth can turn that time into the shorter period and keep it off the window. Because the clocks are recalculated rather than paused, the length and order of the periods matter. A rest of 1 hour 50 minutes does not qualify as the short period.

Exceptions that change the arithmetic

Adverse driving conditions. Snow, ice, sleet, fog, other bad weather, or unusual road or traffic conditions can extend the driving limit and the on-duty window by up to 2 hours. The condition must not have been known, and could not reasonably have been known, to the driver before the duty day began or before driving resumed after a qualifying break, or to the carrier at dispatch¹. A forecast storm does not qualify.

Short-haul. A driver who stays within a 150 air-mile radius of the normal work reporting location and is released within 14 consecutive hours is exempt from keeping a record of duty status. The carrier must instead keep 6 months of time records showing when the driver reported, hours worked and when the driver was released¹. The 2020 rule widened this exception from 100 to 150 air-miles and from 12 to 14 hours, effective September 29, 2020³. Short-haul drivers are also exempt from the 30-minute break, but the daily and weekly limits still apply.

Other exceptions cover agricultural operations during planting and harvest, oilfield work, utility service vehicles and several narrower groups. Alaska has its own limits.

How the rules are enforced

Electronic logging devices. Since December 18, 2017, most carriers subject to the rules must have drivers record duty status on a registered ELD, which logs driving time automatically once the truck moves. Drivers who keep records on no more than 8 days in any 30-day period, certain driveaway-towaway operations, and vehicles built before model year 2000 may still use paper logs¹. Our brief on what an ELD records covers what the device captures and what it leaves out.

Roadside inspections. On request, a driver must transfer the ELD records to the inspector, with records current for the day of inspection and the prior 7 days¹.

Out-of-service orders. Under 49 CFR 395.13, a driver found over the hours limits, or without a current record of duty status, can be ordered out of service on the spot¹. The Commercial Vehicle Safety Alliance’s North American Standard Out-of-Service Criteria, updated each April 1, set the pass-fail conditions inspectors apply⁶. In CVSA’s 2026 International Roadcheck, hours-of-service violations accounted for 929 driver out-of-service orders in North America, 23.4 percent of the total and second only to drivers without a medical card. False records of duty status added another 266⁷.

Carrier audits. Federal and state investigators compare logs against the bills of lading, dispatch records, expense receipts, fleet messages and payroll records that carriers must keep as supporting documents¹.

What hours records show after a crash

After a serious crash, the hours-of-service file is often the first thing investigators and lawyers ask for. Carriers need keep records of duty status and supporting documents for only 6 months¹, so early preservation requests matter. The record can show:

How many hours into the 14-hour window the crash occurred.
Driving time since the last 10-hour break and the last 30-minute interruption.
Where the driver stood against the weekly limit.
Whether off-duty periods met the sleeper-berth rules.
Edits, their annotations, and who requested them.

It cannot show whether the driver slept during time logged off duty, and it does not record speed or braking. Matching the log against supporting documents is how investigators test its accuracy. Our guide to evidence after a truck crash covers that wider set of records, and our analysis of truck driver fatigue covers why hours compliance and alertness are not the same thing.

State rules for intrastate trucking

Part 395 governs interstate commerce. Drivers who operate only within one state fall under that state’s rules, and states that receive federal motor carrier safety grants must keep those rules compatible with the federal regulations. Federal rules allow intrastate hours-of-service variances only within set bounds: a driving limit of up to 12 hours with no driving after 16 hours on duty, weekly limits of up to 70 hours in 7 days or 80 hours in 8 days, and a short-haul radius of 150 air-miles⁵. Whether a state uses that room, and how, depends on its own statutes and regulations. A purely intrastate operation needs to check that state’s code, not Part 395 alone.

The Federal Motor Carrier Safety Regulations: A Reader's Map

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The Federal Motor Carrier Safety Regulations decide who may operate a truck or bus in interstate commerce, for how long, in what condition and with what insurance behind it. Most readers meet them as citations: “49 CFR 395.3” on a roadside inspection report, “§ 396.11” in a lawsuit. This page maps who the rules reach, what the most-cited parts govern, how states carry the rules to trucks that never cross a state line, and where the text and the agency’s guidance live.

Who the rules reach

The rules apply to employers, employees and commercial motor vehicles that transport property or passengers in interstate commerce¹. Both halves of that sentence are defined terms, and both reach further than the plain words suggest.

Interstate commerce has three tests in 49 CFR 390.5T. It covers transport between a place in one state and a place outside it; transport between two places in the same state that passes through another state or country; and transport between two places in one state when the trip is part of a movement that begins or ends outside the state or the country². Under the third test, a truck that never leaves one state can still be in interstate commerce.

Commercial motor vehicle means a self-propelled or towed vehicle used on a highway in interstate commerce to carry passengers or property that meets any one of four tests²:

a gross vehicle weight rating or gross combination weight rating, or an actual gross weight, of 10,001 pounds or more, whichever is greater;
designed or used to carry more than 8 passengers, including the driver, for compensation;
designed or used to carry more than 15 passengers, including the driver, when not carrying them for compensation;
used to carry hazardous materials in a quantity that requires placards under the federal hazardous materials rules.

The weight test reaches well past tractor-trailers, to smaller trucks and to pickup-and-trailer combinations rated at 10,001 pounds or more.

Section 390.3T(f) lists exceptions, among them school bus operations, government transportation, fire and rescue vehicles in emergencies, and some 9-to-15-passenger vehicles not operated for direct compensation¹. Several exceptions keep particular sections in force, so the paragraph has to be read in full.

Two parts reach further. Part 383, the commercial driver’s license rules, applies to every person who operates a commercial motor vehicle in interstate or intrastate commerce¹, and it uses its own, heavier definition: generally 26,001 pounds or more, a vehicle designed to carry 16 or more people including the driver, or hazardous materials³. Part 382, drug and alcohol testing, follows the license and covers drivers subject to the CDL rules and their employers⁴.

The parts, one by one

Eleven parts cover the driver, the vehicle, the trip and the insurance. The right-hand column points to the sections a reader is likely to need first.

Part	Subject	What a reader goes there for
382	Drug and alcohol testing	Pre-employment, post-accident, random, reasonable-suspicion, return-to-duty and follow-up testing (382.301 to 382.311); the Drug and Alcohol Clearinghouse (382.701)
383	Commercial driver’s licenses	The one-license rule, disqualification of drivers (383.51), vehicle groups (383.91), endorsements (383.93)
385	Safety fitness procedures	The safety fitness standard (385.5); satisfactory, conditional and unsatisfactory ratings (385.3); the ban on unsatisfactory-rated carriers (385.13); new entrant audits (Subpart D)
387	Financial responsibility	Minimum insurance by cargo (387.9), the MCS-90 endorsement (387.15), passenger carrier limits (387.33T). See federal minimum insurance
390	General rules	Who is covered (390.3T); definitions, including “accident” (390.5T); the ban on coercing drivers (390.6); the accident register a carrier keeps for 3 years (390.15)
391	Driver qualification	Minimum age of 21 and English proficiency (391.11), job applications and prior-employer inquiries (391.21, 391.23), medical standards (391.41), driver qualification files (391.51)
392	Driving of commercial motor vehicles	No operating while ill or fatigued (392.3), drugs and alcohol (392.4, 392.5), schedules that would require speeding (392.6), texting and hand-held phones (392.80, 392.82). See driver fatigue
393	Parts and accessories	Lamps, brakes (Subpart C), coupling devices, cargo securement (Subpart I), frames, wheels, steering and suspension
395	Hours of service	Driving and duty limits (395.3, 395.5), exceptions (395.1), records of duty status and electronic logging devices (395.8, Subpart B). See hours of service and ELD records
396	Inspection, repair and maintenance	Systematic maintenance and records (396.3), roadside out-of-service orders (396.9), driver vehicle inspection reports (396.11), annual inspections (396.17). See maintenance failures
397	Hazardous materials: driving and parking	Attendance of loaded vehicles (397.5), parking (397.7), routing (Subparts C and D)

Two parts produce the numbers quoted most often: Part 395’s 11 hours of driving inside a 14-hour window, with caps of 60 hours in 7 days or 70 in 8⁶, and Part 387’s $750,000 floor for general freight⁷. The “accident” defined in 390.5T, an occurrence that results in a death, an injury treated away from the scene or a vehicle towed away with disabling damage², is what a carrier must log in its accident register.

The subchapter also covers operating authority (365), brokers (371), vehicle leasing (376) and record preservation (379)⁵. A liability question after a crash often draws on several parts at once; see liability in commercial vehicle collisions.

How states carry the rules to intrastate carriers

The FMCSRs bind interstate commerce. A truck that stays inside one state, on a trip that is not part of an interstate movement, answers to that state’s laws. Federal grant money links the two.

To qualify for Motor Carrier Safety Assistance Program funds, a state must adopt and enforce commercial vehicle safety laws compatible with the federal rules⁸. It reviews its laws each year and has no more than three years after a federal change takes effect to match it⁹. FMCSA can withhold funds from a state with an incompatible provision¹⁰.

For intrastate commerce, Section 350.305 lists the departures a state may make¹¹:

exempting intrastate vehicles under 26,001 pounds, unless they carry placarded hazardous materials or are designed or used to carry 16 or more people;
allowing 12 hours of driving with no driving after 16 hours on duty, weekly limits of 70 hours in 7 days or 80 in 8, and a 150 air-mile radius (or the federal short-haul radius, if greater);
a minimum driver age of 18;
keeping drivers qualified under earlier state medical standards, and medical variance programs;
other variances, on application to FMCSA.

A state may not exempt carriers by type of operation, such as for-hire or private, apart from unchanged industry exemptions that predate April 1988, or by distance from the work reporting location beyond the distance exemptions in the FMCSRs themselves¹¹. Intrastate hazardous materials carriers are a partial exception: Section 390.3T(g) applies parts of the federal rules to them directly¹.

The result is a federal floor with a defined set of permitted departures. Which ones a state adopted is a question for its own statutes and administrative code.

Where the text lives

The current text is on the eCFR, the Electronic Code of Federal Regulations, in Title 49, Subtitle B, Chapter III, Subchapter B⁵. The eCFR is updated daily and describes itself as an editorial compilation of CFR material and Federal Register amendments, not yet an official legal edition¹². It keeps dated earlier versions of each section, which matters when the question is what the rule said on the day of a crash.

FMCSA’s interpretations sit elsewhere, in the agency’s Regulatory Guidance portal. The portal states that guidance documents lack the force and effect of law unless a statute authorizes them or a contract incorporates them¹³. Guidance shows how the agency reads a rule. It is not the rule.

The out-of-service criteria are a separate document

Roadside inspections bring in a third text. The North American Standard Out-of-Service Criteria come from the Commercial Vehicle Safety Alliance, a nonprofit association of commercial vehicle safety officials and industry representatives. CVSA calls them the pass-fail criteria for inspections: the violations serious enough to take a driver, vehicle or load off the road until fixed. They are updated every year, effective April 1¹⁴.

The criteria are not part of the FMCSRs. The authority to stop a truck comes from the regulations: Section 396.9 lets FMCSA personnel put a vehicle out of service when its condition or loading would likely cause an accident or a breakdown¹⁵, and Section 395.13 covers drivers over their hours or without current duty-status records¹⁶. Part 385 incorporates the criteria by reference for carriers that hold hazardous materials safety permits¹⁷.

The regulation says what a carrier and driver must do. The criteria say when a shortfall is serious enough to stop the truck at the roadside.

Federal Minimum Insurance for Motor Carriers: The $750,000 Floor

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The federal insurance floor for a for-hire truck hauling ordinary freight across state lines is $750,000 per accident. The figure sits in 49 CFR 387.9 under a column headed “January 1, 1985”¹, and it has not moved since. Many carriers buy more. But it is all federal law requires to stand behind such a truck in a crash, and above the 10,001-pound line it turns on what the truck carries, not on how heavy it is or how much harm a crash can do.

The schedule

Section 387.9 sets four public liability tiers for vehicles carrying property¹:

Who	Cargo	Minimum per accident
For-hire carriers, interstate or foreign commerce, vehicles of 10,001 lb GVWR or more	Nonhazardous property	$750,000
For-hire and private carriers, 10,001 lb or more; any quantity interstate, bulk only intrastate	Oil, and hazardous waste, materials and substances not in the $5 million tiers	$1,000,000
For-hire and private carriers, 10,001 lb or more, interstate, foreign or intrastate	Hazardous substances in bulk tanks or hoppers; bulk explosives, gases and poison-inhalation materials; highway-route-controlled radioactive shipments	$5,000,000
For-hire and private carriers, under 10,001 lb, interstate or foreign	Bulk explosives and poison-inhalation materials; highway-route-controlled radioactive shipments	$5,000,000

The schedule reaches for-hire property carriers in interstate or foreign commerce, and any carrier hauling hazardous materials, including bulk loads inside one state. Vehicles under 10,001 pounds fall outside it unless they carry the most dangerous cargo². A separate filing rule sets $300,000 for for-hire fleets made up only of vehicles under 10,001 pounds carrying nonhazardous property³.

A carrier proves coverage with an MCS-90 insurance endorsement, an MCS-82 surety bond or FMCSA authorization to self-insure, kept at its principal place of business. The proof is public information and must be produced on reasonable request by a member of the public⁴. FMCSA points readers to its licensing and insurance system for a carrier’s insurance status¹⁸.

Passenger carriers

Section 387.33T, the version of 387.33 in force, sets the passenger schedule. For-hire carriers of passengers in interstate or foreign commerce need $5,000,000 for a vehicle seating 16 or more, counting the driver, and $1,500,000 for 15 or fewer⁵. The rule excludes vehicles carrying only school children and teachers to or from school, small taxicabs, commuter vehicles carrying fewer than 16 people and contracted school extracurricular trips⁶. The passenger endorsement is Form MCS-90B.

What the MCS-90 does

The MCS-90 is attached to the carrier’s liability policy and applies to every vehicle operated under it, not to a list of trucks⁸.

Its central promise runs to the public. The insurer agrees to pay, up to the endorsement’s limits, any final judgment against the insured carrier for public liability resulting from negligence in the operation, maintenance or use of vehicles subject to the federal requirements. That holds whether or not the vehicle is described in the policy and wherever the crash happens. No condition, limitation or breach of the policy relieves the insurer of that payment, and neither does the carrier’s insolvency or bankruptcy⁷.

The cost is meant to land on the carrier. The form keeps the policy’s terms binding between insurer and carrier, and the carrier agrees to reimburse the insurer for any payment it would not have owed except for the endorsement⁷. The injured party collects; the insurer then has a claim against its own customer.

The guarantee is narrow. It excludes injuries to the carrier’s own employees on the job, and cargo. Its limits apply separately to each accident⁷, so everyone hurt in one crash draws on the same amount. In 2005, after denying a petition from insurers to amend the form, FMCSA issued guidance that the endorsement does not require an insurer to pay a judgment against anyone other than the carrier named in it⁹.

Unchanged since 1985

Congress set the amounts in the Motor Carrier Act of 1980, and the statute still says the property level “shall be at least $750,000”¹⁰. The Department of Transportation phased the levels in at lower amounts, then on January 1, 1985 set them at the lowest levels the act allowed. In FMCSA’s words in 2014, “the levels have remained unchanged since”¹¹. FMCSA can raise the minimums by regulation. It has not.

The last rulemaking attempt ran from 2014 to 2017. FMCSA’s November 2014 advance notice cited its own report to Congress, which concluded the minimums were inadequate to cover the costs of some crashes. It summarized a study by DOT’s Volpe Center: crashes with claims above the minimums were estimated at under 1 percent of commercial vehicle crashes, crashes in the most severe injury categories could exceed $1 million, and medical prices rose 4.9 percent a year from 1985 to 2013, against 2.8 percent for the consumer price index excluding food and energy¹¹.

The notice set out evidence pointing both ways. The Pacific Institute for Research and Evaluation and the Trucking Alliance, a group of trucking companies, each concluded the floor was too low. The American Trucking Associations’ review of data from two large trucking insurers found that most policies on trucks over 26,000 pounds were already written at $1 million or more, and put the chance of a claim above $1 million at 0.73 percent¹¹. The notice’s questions also covered the concerns on the other side: whether a higher floor would affect small and large carriers differently, and whether carriers could still obtain insurance.

FMCSA withdrew the notice in June 2017. It had received 2,181 comments but said they lacked the cost and benefit data a rule would need. The agency said it could not estimate how much premiums would rise, how insurers’ capital requirements would change, or what crash victims would gain¹².

Congress has considered changing the statute directly. Section 4408 of H.R. 2, an infrastructure bill in the 116th Congress, would have raised the $750,000 figure to $2,000,000 and required inflation adjustments every five years. The House passed the bill on July 1, 2020, by 233 to 188. Its last recorded action is receipt in the Senate on July 20, 2020¹³.

Brokers and freight forwarders: $75,000, for a different purpose

A freight broker must keep a $75,000 surety bond or trust fund to hold FMCSA registration¹⁴. The statute fixes the amount regardless of how many offices or agents the broker has, and sets the same $75,000 for freight forwarders¹⁵¹⁶.

The bond is not crash coverage. It pays shippers or motor carriers when a broker fails to carry out its transportation contracts, such as by not paying freight charges¹⁴¹⁵. A 2023 rule, with provisions in force since January 16, 2026, lets FMCSA suspend a broker’s authority when the bond or trust drops below $75,000 and is not restored¹⁷¹⁴. Neither bond is designed to pay people hurt in a crash.

Why serious crashes outrun the floor

The minimum is one per-accident amount shared by everyone hurt in a crash, and a crash with several seriously injured people can produce claims far beyond it. The floor has stayed fixed while medical costs climbed, and FMCSA’s 2014 notice said coverage at the statutory minimum does not cover as much of a catastrophic crash as it once did¹¹.

Carriers that buy higher limits or excess and umbrella policies raise what is available. Where a carrier holds only the minimum, claimants look to the carrier’s own assets and to other parties who may share responsibility, such as a shipper, broker, maintenance contractor or vehicle manufacturer. Whether any of them is liable depends on the facts and on state law; see liability in commercial vehicle collisions. For where Part 387 sits among the other safety rules, see the reader’s map to the FMCSRs.

Evidence After a Commercial Vehicle Crash: What Disappears First

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Within minutes of a serious truck crash, evidence starts to go. Tire marks fade under traffic. A looping camera writes over itself. Alcohol leaves a driver’s blood. Carrier records last longer because federal rules set minimum retention periods, but those are counted in months, and some run out before a dispute takes shape.

This guide sorts the main kinds of evidence by how fast they tend to disappear. Exact timing depends on the agency, the company, the equipment and the state.

The first hours: the scene

Marks on the road are the most perishable evidence and among the most useful. Tire marks show where a vehicle braked, yawed or slid, and their length feeds speed estimates. Gouges help fix the point of impact. Debris, fluid trails and rest positions show how vehicles moved after contact.

Most of this is gone once the road reopens. Wreckers remove the vehicles, crews sweep debris, and traffic and weather wear down the marks. What survives is what someone recorded: police photographs and measurements, the crash report diagram, a reconstructionist’s scan, a bystander’s video. How much the official file holds varies with the crash and the agency.

The first hours: post-accident testing

Federal rules put the tightest clock on drug and alcohol testing of the commercial driver. Under 49 CFR 382.303, the motor carrier must test each of its surviving drivers as soon as practicable after certain crashes on public roads¹:

Fatal crashes. Alcohol and controlled-substance tests are required for any surviving driver who was performing safety-sensitive functions with respect to the vehicle, cited or not.
Injury or tow-away crashes. Tests are required when a person was injured and immediately received medical treatment away from the scene, or a vehicle had disabling damage requiring a tow, and the commercial driver is cited for a moving violation arising from the crash. For alcohol, the citation must come within 8 hours; for controlled substances, within 32 hours.

If an alcohol test is not given within 2 hours, the carrier must record why. After 8 hours it must stop trying and record that as well. A controlled-substance test not given within 32 hours is abandoned on the same terms¹. Breath, blood or urine tests by police acting under their own authority can satisfy the rule if they meet applicable requirements and the carrier obtains the results.

The paperwork outlasts the samples: negative results are kept one year, documents on post-accident testing decisions two years, and positive results and refusals five years².

Hours to days: data in the vehicles

A truck’s engine control module may hold event records triggered by hard braking or a collision, a last stop record and trip data. Later events can overwrite them, and the engine maker Detroit warns that if power is interrupted while the module is writing, “more than likely data will be lost”³. Starting, towing, repairing or salvaging the truck all carry that risk. What these modules typically record and how the data is retrieved: What Data Is Stored in a Commercial Truck’s Electronic Control Module?

Cameras can go faster. Forward-facing and driver-facing units commonly record on a loop and keep only clips flagged by an event or saved by the fleet; how long the rest survives depends on storage and settings. Telematics data sits on a vendor’s servers as long as the contract allows.

The other vehicles matter too. A passenger car’s event data recorder must lock its record when a frontal air bag deploys, but records of crashes without a deployment may be overwritten by later events⁴. Damaged cars are often repaired, sold or crushed, and the recorder goes with them.

Days to weeks: public records

Cities, counties and state transportation departments hold records that can settle who had the light: signal timing plans, controller and malfunction logs, traffic camera footage, and 911 and dispatch recordings. Each agency keeps them on its own schedule, usually under state records law. Some traffic cameras only stream live and record nothing. Recorded footage may be overwritten quickly, and a public records request can take longer to answer than the footage lasts.

Cameras on nearby businesses, buses and homes are more fragile still. Private systems often overwrite on short cycles, and nothing requires their owners to keep anything.

Weeks to months: witnesses

Witness accounts have no fixed expiration, but they wear away. People move and change numbers. Details blur, and memory can absorb what a witness later heard or read. A statement taken soon after the crash, in the witness’s own words and noting where the witness stood, carries more weight than one gathered a year later.

Months to years: carrier records

Federal safety rules require motor carriers to keep many records for set minimum periods:

Driver vehicle inspection reports: 3 months from the date the report was prepared, with the certification of repairs⁵.
Hours-of-service records: records of duty status, including ELD records, and supporting documents such as bills of lading, dispatch records, expense receipts, fleet messages and payroll records, kept at least 6 months⁶. More in What an Electronic Logging Device Records.
Maintenance records: 1 year where the vehicle is housed or maintained, and 6 months after the vehicle leaves the carrier’s control⁷.
Annual inspection reports: 14 months from the date of the report⁸.
Accident register: 3 years after each accident⁹.
Driver qualification file: for the length of the driver’s employment and 3 years after, though some items, such as annual driving record reviews and medical certificates, may be removed 3 years after they were made¹⁰.

These are regulatory floors. They do not decide what a company must keep once a claim or lawsuit is anticipated; that is a question for preservation law. Why these files matter in a dispute over fault is covered in Understanding Liability in Commercial Vehicle Collisions.

The clocks at a glance

Evidence	Usually held by	Typical lifespan
Tire marks, debris, fluids	The roadway	Until cleared or worn away
Post-accident alcohol test	Carrier	8-hour window
Post-accident drug test	Carrier	32-hour window
ECM event records	Carrier or truck owner	Until overwritten or lost
Loop camera footage	Carrier or vendor	Until overwritten
Signal logs, traffic video	City or state agency	Agency schedule
Witness memory	Witnesses	Fades with time
Inspection reports (DVIRs)	Carrier	3 months minimum
ELD records	Carrier	6 months minimum
Annual inspection reports	Carrier	14 months minimum
Maintenance records	Carrier	1 year, plus 6 months after disposal
Accident register	Carrier	3 years

What a preservation letter is

A preservation letter, sometimes called a spoliation letter, is a written notice to whoever holds evidence. It identifies the crash, lists what the sender wants kept (engine data, camera footage, ELD and dispatch records, maintenance files, the vehicles themselves) and asks that nothing be altered or destroyed. Letters commonly go to the motor carrier, its insurer, the trailer owner, the tow yard and public agencies. Preservation runs both ways: carriers and insurers also move to secure the other vehicle’s recorder and the scene.

A letter is not a court order. Its main effect is notice, which can matter if evidence later goes missing. A court can be asked to order preservation or an inspection.

The idea of spoliation

Spoliation is the destruction or alteration of evidence, or the failure to preserve it, by someone with a duty to keep it. Courts that find spoliation respond in graduated ways, from letting the jury hear about the loss to excluding evidence, instructing jurors that they may infer the missing material was unfavorable, or in serious cases dismissing a claim or entering a default.

In federal court, Rule 37(e) governs lost electronically stored information. If information that should have been preserved is lost because a party failed to take reasonable steps, and it cannot be restored or replaced, a court that finds prejudice to another party may order measures no greater than necessary to cure it. It may presume the information was unfavorable, instruct the jury to that effect, or dismiss the action or enter a default only on finding that the party acted with intent to deprive the other side of it¹¹. State courts apply their own rules on when a duty to preserve arises and what remedies follow, and the answer in any case turns on its facts.

What an Electronic Logging Device Records, and What It Does Not

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Since December 18, 2017, most interstate truck drivers have recorded their hours of service on an electronic logging device. Carriers that had already installed older automatic onboard recording devices had until December 16, 2019 to switch¹. The ELD is often the first record requested after a serious crash. It answers some questions very well and others not at all.

What it records

An ELD connects to the truck’s engine and records a fixed set of data elements: date, time, the vehicle’s location, engine hours, vehicle miles, and identification for the driver, the vehicle and the motor carrier¹. It records them at every change of duty status, at engine power-up and shutdown, and at least once an hour while the truck is moving. Logins, logouts and device malfunctions are time-stamped as well.

Driving time is automatic. When the truck’s speed passes a threshold that cannot be set higher than 5 miles per hour, the device switches the driver’s status to driving¹. The other statuses (off duty, sleeper berth, on duty not driving) are entered by the driver.

Location is deliberately coarse. During on-duty driving, the recorded position is accurate to about a 1-mile radius. During authorized personal use of the truck it drops to about a 10-mile radius¹².

The device also keeps a separate “Unidentified Driver” account. If the truck moves with no one logged in, the driving goes there. Drivers and carriers must review it and either assign the time to a driver or annotate why it is unassigned. Carriers keep those records for at least 6 months¹.

What it does not record

An ELD is not a speed recorder or a crash recorder. FMCSA says plainly that ELDs “are not required to collect data on vehicle speed,” and that the ELD rule does not require real-time tracking². The device uses speed only to decide whether the truck is moving. It does not log the speed curve, brake application, throttle position or a hard-braking event.

That data lives elsewhere: in the engine control module and in any telematics or camera systems the carrier runs, each with its own retention behavior. Our explainer on what a truck’s engine control module stores covers them. Many carriers buy ELD and telematics functions from one vendor on shared hardware, so a request for “the ELD data” alone may miss what the rest of the system holds.

Nor can the ELD say whether a driver slept. It shows when the driver was logged off duty or in the sleeper berth, not what happened then.

Edits and annotations

Drivers can edit their logs, within limits. Every change or addition must carry an annotation. A carrier may propose edits, but the driver must accept or reject them and recertify the record, and carriers may not coerce a false certification¹.

Two limits matter most after a crash. Automatically recorded driving time cannot be shortened by edit. And the original records survive. FMCSA’s guidance says “the original ELD records are retained even when allowed edits and annotations are made”², and the regulation bars carriers from altering or erasing the original data¹. The edit history, showing what was changed, when and at whose request, is often as informative as the final log.

Personal conveyance and yard moves

A carrier may configure the ELD to let a driver flag two special driving categories: authorized personal use and yard moves. The driver selects the category before the movement and clears it after¹.

Personal conveyance is driving a truck for personal reasons while off duty. FMCSA’s 2018 guidance allows it to be logged off duty only when the driver has been relieved from work and all responsibility for performing work by the carrier. The truck may be loaded, since the load is not being moved for the carrier’s commercial benefit at that time³. Driving to a nearby, reasonable, safe place to rest after loading or unloading can qualify. Driving to the carrier’s terminal after a delivery does not³. Because personal conveyance does not count as driving time, it is a recurring point of dispute when a crash happens during it.

Retention and supporting documents

Carriers must keep ELD records and supporting documents for 6 months, and keep a backup copy on a separate device¹². Supporting documents are the business records used to check the log: bills of lading or other trip documents, dispatch records, expense receipts, fleet management messages, and payroll or settlement records. A carrier need not keep more than eight per driver per day, but must keep those with the earliest and latest times¹.

Drivers must keep the current day and the previous 7 days available for inspection while on duty¹.

How the records are requested

At roadside, the driver transfers the data to the inspector. Devices must support one of two transfer methods: telematics (wireless web services and email) or local transfer (USB and Bluetooth)². The output follows a standard file format set in the regulation’s technical appendix¹.

After a crash, the carrier holds the records and must produce them electronically when an authorized safety official asks¹. In civil litigation they are sought through preservation letters and discovery, under rules that vary by court and state. The 6-month retention period is the practical clock: a request that arrives later may find only what the carrier chose to keep. Our guide to evidence after a truck crash covers how ELD data fits with the other records, and our hours-of-service explainer covers the limits the log is measured against.

Distracted Driving and Motorcycle Crashes: Why Riders Carry the Risk

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A driver waits to turn left across oncoming traffic. They look, judge the gap, and go. The vehicle they misjudged, or never registered at all, is a motorcycle. In a crash between two cars, a short lapse like that often ends with bent metal and a tow. Against a motorcycle, the same lapse can kill the rider.

That imbalance is the heart of the problem. In 2024, 6,228 motorcyclists were killed in U.S. traffic crashes, 16 percent of all traffic deaths that year, according to NHTSA.¹ Measured per mile traveled, the gap is wider. NHTSA put the 2024 motorcyclist fatality rate at 28.00 deaths per 100 million vehicle miles traveled, almost 27 times the rate for passenger car occupants, which was 1.05.¹ Distraction is not the only reason for those numbers. It is one of the ways a driver’s error lands hardest on someone else.

Why the same lapse costs a rider more

No crash structure. A car surrounds its occupants with a frame designed to absorb energy, plus seat belts and airbags. A rider has a helmet and whatever gear they chose to wear that day. When a car and a motorcycle meet, the rider’s body absorbs forces the car’s occupants are shielded from.

A small target. NHTSA’s guidance to drivers notes that a motorcycle’s smaller size means it can be hidden in a vehicle’s blind spot.¹ A pillar, a mirror or a car in the next lane can cover a motorcycle entirely.

Hard to read. NHTSA also says a motorcycle’s “size and narrow profile can make it difficult to judge its distance and speed.”¹ A driver deciding whether there is time to turn is doing rough physics in a second or two. With a car, the shape grows in the windshield and gives cues about closing speed. A single headlight and a narrow frame give fewer.

Add a distraction and the margins shrink further, because a driver with divided attention has even less time to pick a small shape out of traffic.

“Looked but failed to see”

Crash investigators have a name for one of the most frustrating crash types: the driver looked in the right direction and did not see the motorcycle. The Federal Highway Administration’s Motorcycle Crash Causation Study, which sent investigators to motorcycle injury crashes in Orange County, California, set out to measure how often other drivers gave that account.² In the study’s coded responses from drivers of the other vehicles involved, 12 percent reported they “Looked, but Didn’t See” the motorcycle. By comparison, 1 percent reported being distracted by a device and 3 percent by an outside event or person, while 79 percent described themselves as attentive and not distracted.² These are the drivers’ own accounts, collected for crashes in the study’s sample during the period its February 2019 final report covers (January 2011 to December 2017). They are not a national rate.

The category blurs a line people like to draw. A driver who looked and failed to register a rider was not necessarily holding a phone. They may have been thinking about something else, scanning for cars rather than motorcycles, or looking where the rider blended into a busy background. The study’s investigators recorded whether that background made the motorcycle more or less noticeable.²

In NHTSA’s crash causation research, failures like these fall under “recognition errors,” the largest group of driver errors in its sample, which includes inattention, distraction and inadequate surveillance.⁶ Our explainer on what share of crashes involve human error covers how NHTSA defines and counts them.

The left turn across a rider’s path

One crash pattern recurs throughout motorcycle research. A vehicle turns left, usually at an intersection or driveway, across the path of a motorcycle that is going straight, passing or overtaking.

The FHWA causation study found left-turn scenarios to be the most common crash configuration in its sample.² NHTSA’s national data on fatal crashes show the same pattern. In 2024 there were 3,396 fatal two-vehicle crashes involving a motorcycle and another type of vehicle. In 45 percent of them (1,532 crashes), the other vehicle was turning left while the motorcycle was going straight, passing or overtaking.¹ Those figures describe the vehicles’ movements, not who was at fault.

The left turn combines every weakness described above. The driver must judge the speed and distance of an oncoming vehicle that is hard to judge, often while also watching pedestrians, the signal and the car behind. When that judgment fails, the rider has seconds or less to brake or swerve, and no structure around them to absorb the impact.

Three kinds of distraction

Federal agencies describe distraction in three types. The CDC defines them plainly:³

Visual: “taking your eyes off the road”
Manual: “taking your hands off the wheel”
Cognitive: “taking your mind off driving”

NHTSA used the same three categories in its 2010 overview of its driver distraction program, describing visual distraction as tasks that require the driver to look away from the roadway and manual distraction as tasks that require taking a hand off the wheel to manipulate a device.⁴

For riders, the cognitive type deserves attention. A driver on a hands-free call can keep both eyes forward and both hands on the wheel and still fail to process what is in front of them. That is the “looked but failed to see” crash in another form, and it is the type of distraction least likely to show up in any record.

Why police reports undercount distraction

Most national counts of distraction-affected crashes come from police crash reports, through NHTSA’s Fatality Analysis Reporting System and its Crash Report Sampling System. NHTSA is direct about the limits.⁵

The forms differ. Police report forms vary by jurisdiction. Some include a distraction field; others leave it to the officer’s narrative. NHTSA says any national or state count “should be interpreted with this limitation in mind due to potential underreporting in some States and overreporting in others.”
Drivers rarely volunteer it. The only source of distraction information may be the surviving driver’s own account, and NHTSA notes that the likelihood of a driver admitting to texting “might be small.”
Fatal crashes remove a witness. When a driver dies, officers must rely on the investigation and witness accounts, which may not exist.
Terms blur. NHTSA treats distraction as a subset of inattention, but its 2024 note says the two terms “are often used interchangeably or simultaneously” in other material, including police reports.

Cognitive distraction is close to invisible in this system. There is no device to find and often nothing to admit. For more on how these federal data sets are built and what each one can answer, see our field guide to U.S. crash data.

What drivers and riders can each do

Drivers

NHTSA’s advice to drivers is specific to motorcycles:¹

Always look for motorcyclists, and check blind spots, where a motorcycle can be hidden.
Take extra care when judging when to turn or merge. A motorcycle’s speed and distance are hard to read.
Leave a safe following distance. Riders can slow by downshifting, which does not turn on the brake light.
Expect riders to change position within a lane to avoid debris.

Beyond that, the most useful step is the plainest one: keep the phone out of reach while the car is moving, and end a call or conversation when traffic gets complicated.

Riders

NHTSA’s advice to riders centers on being seen and being protected.¹ It recommends high-visibility colors and retroreflective materials, protective gear, and a helmet carrying the DOT label. It also says riding “requires full attention, skill, and coordination,” which applies to a rider’s own phone as much as to a driver’s.

At intersections, the left-turn pattern suggests a working assumption: a vehicle waiting to turn across your path may not have seen you. Slowing, covering the brakes and choosing a lane position that keeps you in the driver’s view all buy time if that assumption turns out right.

What the data cannot tell us

This page’s URL asks whether distracted driving is a leading cause of motorcycle crashes. The honest answer is that federal data cannot rank it. Distraction is underreported in police records for the reasons NHTSA lists. The “looked but failed to see” crash may involve no device at all. And national fatality data record what officers could document, not what was going on inside a driver’s head.

The studies that look closer have their own limits. The FHWA causation study is detailed but drew its crashes from a single California county.² Its findings describe that sample and should not be projected onto the whole country.

What the evidence does support is narrower and still useful: a recurring crash pattern in which drivers fail to see or correctly judge an oncoming motorcycle, and a gap in protection that turns those failures into deaths far more often for the rider than for the driver.

Deer Collisions in Virginia: Statistics, Seasonal Risk and What Follows a Strike

2026-10-07T00:00:00Z

Most deer collisions in Virginia never become a crash statistic. The driver pulls over, checks the grille, maybe calls an insurer, and drives on. No officer writes a report, so the crash never reaches the state database. That gap shapes every number on this page, and it is the first thing to understand before quoting one.

The numbers

Virginia’s official crash counts come from police crash reports, which the Department of Motor Vehicles collects in the Traffic Records Electronic Data System, known as TREDS.¹ The table below is where the most recent statewide figures belong.

Year	Deer-related crashes	Injuries	Fatalities
2025	[Verified statistic and source required: Virginia deer-related crashes, 2025; Virginia DMV TREDS crash data]	[Verified statistic and source required: injuries in Virginia deer-related crashes, 2025; Virginia DMV TREDS]	[Verified statistic and source required: deaths in Virginia deer-related crashes, 2025; Virginia DMV TREDS]
2024	[Verified statistic and source required: Virginia deer-related crashes, 2024; Virginia DMV TREDS crash data]	[Verified statistic and source required: injuries in Virginia deer-related crashes, 2024; Virginia DMV TREDS]	[Verified statistic and source required: deaths in Virginia deer-related crashes, 2024; Virginia DMV TREDS]
2023	[Verified statistic and source required: Virginia deer-related crashes, 2023; Virginia DMV TREDS crash data]	[Verified statistic and source required: injuries in Virginia deer-related crashes, 2023; Virginia DMV TREDS]	[Verified statistic and source required: deaths in Virginia deer-related crashes, 2023; Virginia DMV TREDS]

Source note for this table: police-reported crashes only. [Verified statistic and source required: the TREDS query used for the table (collision type “deer” or the separate animal or deer field), the date the data were pulled, and whether the most recent year is final or preliminary.]

How the count is pulled matters. In a 2017 review, the Virginia Transportation Research Council, the research arm of the Virginia Department of Transportation, ran the same year of police reports through two state query tools. Searching the “Collision Type” field for deer returned 5,593 crashes in 2016. A separate deer field, which also caught crashes such as a rear-end collision after a driver braked hard for a deer, returned 7,544.²

Why the official count runs low

Police reports are not filed for every crash. Virginia law requires an officer who investigates a crash to send a report to DMV when someone is hurt or killed, or when property damage appears to reach $3,000 or more.³ A report depends on an officer being called in the first place, and VTRC notes that many drivers do not notify police after hitting an animal.²

The researchers measured the gap. In the areas they examined, deer carcass removal records showed up to 8.5 times as many deer collisions as police reports did. Statewide, from 2012 through 2016, deer crashes in police reports equaled about 1 in 7.7 of deer-collision insurance claims.² For 2016, the report set about 7,500 police-reported deer crashes against an insurance-based estimate of 61,141.²

Virginia’s Wildlife Corridor Action Plan, completed in May 2023 by four state agencies, puts the scale this way: “More than 60,000 known deer-vehicle collisions have occurred annually in Virginia since 2015.”⁴ That figure is far above the police-reported count and in line with the insurance-based estimates VTRC used. Anyone quoting a Virginia deer-crash number should say which kind it is.

What insurers estimate

Insurers publish their own measures of deer-strike risk by state, usually as the odds that a driver will file an animal-collision claim in a year.

Virginia drivers’ odds of an animal-collision claim: [Verified statistic and source required: Virginia odds of an animal-collision insurance claim and the reporting period; the insurer’s own published claims study, cited to its release]
Virginia’s national rank: [Verified statistic and source required: Virginia’s rank among states for animal-collision claims, same insurer study and period]
Average claim cost: [Verified statistic and source required: average animal-collision claim cost, national or Virginia; insurer or industry source with year]

Treat these with care. FHWA’s 2008 report described one such national estimate, built by scaling one insurer’s claims up to the whole market. It cautioned that the method can miss drivers who lack the coverage that pays for deer damage, and can run high if drivers blame a deer for damage that had another cause.⁵

When the risk peaks

Fall. Deer activity climbs in autumn, and the breeding season, or rut, runs from about October through December. Virginia’s Wildlife Corridor Action Plan identifies November as the worst month for collisions, followed by October and December.⁴

Dawn and dusk. Deer move most around first and last light. National crash data in FHWA’s 2008 report to Congress show the expected peaks in early morning and evening.⁵ In late fall, once the clocks change, dusk arrives around the evening commute.

Two-lane roads. FHWA found that 89 percent of wildlife-vehicle collisions in national crash databases for 2001 to 2005 occurred on two-lane roads, and that such crashes were more common on low-volume roads.⁵ Highways are not exempt. On a 30-mile stretch of Interstate 64 in Albemarle County, VTRC found deer collisions among the most common crash types in police reports, and carcass removal records put deer collisions at roughly three to five times the next most frequent types.²

Why swerving is often worse than braking

Almost every wildlife-vehicle collision involves a single vehicle: 98.5 percent in one crash data set FHWA analyzed and 99 percent in another.⁵ Fatal ones are more likely to involve something else. In federal fatal-crash data on animal-related crashes, the two most common collision types other than striking the animal were hitting another vehicle and overturning. FHWA said that pattern reinforces the view that swerving to avoid an animal may lead to a more severe crash.⁵

The logic is simple. A deer weighs far less than a tree, a utility pole or an oncoming car. A driver who brakes firmly and stays in the lane is usually choosing the smaller collision. The National Association of Insurance Commissioners puts it plainly: “If you do swerve, you could lose control and hit a tree or veer into oncoming traffic.”⁶ And one deer that crosses safely is often followed by another.

A driver who brakes firmly and stays in the lane is usually choosing the smaller collision.

What follows a strike

Safety first. Get the vehicle out of traffic if it can be driven, turn on the hazard lights, and stay away from an injured deer, which can lash out with hooves or antlers.

Notify police when required. Virginia law requires the driver, or someone acting for the driver, to notify law enforcement immediately when a crash causes injury or death.⁷ NAIC also advises alerting authorities when the car cannot be moved or the carcass is blocking traffic, so the road can be cleared.⁶ Ask your insurer whether it wants a police report for an animal claim.

Document it. NAIC advises photographing the vehicle damage, the roadway and any injuries.⁶ The time, the location and the names of any witnesses help as well.

Check the coverage. Damage from hitting an animal usually falls under comp (other-than-collision) coverage, not collision coverage. A swerve into a guardrail or another car can turn the claim into a collision claim. Policies differ, and liability-only policies generally do not pay for damage to the driver’s own car. We cover the details in Deer Strikes and Auto Insurance.

The deer itself. Virginia lets a driver who kills a deer in a collision claim it for personal use, after reporting the collision to a conservation police officer or other law-enforcement officer, who issues a call or report number.⁸

When a deer strike becomes a multi-vehicle crash

A deer is no one’s legal fault. In a single-vehicle strike there is usually no other party to hold responsible, so the driver’s own insurance does most of the work.

That changes when other vehicles are involved: a driver brakes hard for a deer and is rear-ended, or swerves across the center line into an oncoming car. Negligence now matters, and Virginia handles it differently from most states.

Virginia follows pure contributory negligence. A plaintiff found even slightly at fault is generally barred from recovering damages. The Supreme Court of Virginia has repeated that “a negligent plaintiff may recover only if his negligence was a remote rather than a proximate cause of the accident.”⁹ Most states instead use some form of comparative negligence, in which a plaintiff’s share of fault reduces the award, at least up to a threshold, rather than eliminating it.

That makes the details of a chain-reaction crash weigh heavily in Virginia. An argument that a driver was speeding, following too closely or not watching the road can decide a claim outright. Exceptions exist. One is the last clear chance doctrine; in that 2017 decision, the court held that a plaintiff’s continuing negligence does not automatically bar its use.⁹ How these rules apply depends on the facts and on Virginia case law. This page explains the general framework and is not legal advice.

What roads can do

Driver caution only goes so far against an animal that bolts from the treeline. The engineering answer has a strong record.

FHWA’s 2008 report to Congress found that wildlife fencing, with or without crossing structures, reduced collisions with deer and other large animals by 87 percent on average across the studies it reviewed, with a range of 80 to 99 percent.⁵ Fencing by itself can cut animals off from habitat across the road, and animals are more likely to break through when safe crossings are too few or too far apart. So fences are usually paired with underpasses or overpasses, and with escape ramps, called jump-outs, for animals that end up on the road side.⁵

Virginia has tested the approach on its own roads. VTRC researchers added about a mile of 8-foot fencing at each of two existing underpasses on I-64. After installation, deer-vehicle collisions fell 96.5 percent at one site and 88 percent at the other, with no increase within a mile of the fence ends.¹⁰ The state’s action plan reports that crash savings covered the cost in about 1.8 years.⁴

State law now directs that work. Code of Virginia § 29.1-579 requires the Department of Wildlife Resources, working with VDOT, the Department of Forestry and the Department of Conservation and Recreation, to identify areas with a high risk of wildlife-vehicle collisions and to prioritize and recommend crossing projects.¹¹ The resulting Wildlife Corridor Action Plan maps those areas.⁴ [Verified statistic and source required: name, location and status of a current or planned Virginia wildlife crossing or fencing project, if the piece is to cite one; VDOT project page or the Wildlife Corridor Action Plan’s latest update]

A Field Guide to U.S. Crash Data: FARS, CRSS, MCMIS and the Causation Studies

2026-10-07T00:00:00Z

Texas recorded 608 deaths in commercial motor vehicle crashes in 2024 by its own count and 720 deaths in large-truck crashes by the federal one¹⁶². Neither number is wrong. Each U.S. crash data system was built for one purpose: to count every death, to estimate the much larger pool of police-reported crashes, to track motor carriers, or to study why crashes happen. The numbers carry those purposes with them. This guide covers who publishes each source, what it counts and leaves out, how fast it arrives, and the trap each one sets for reporters.

The sources at a glance

Source	Publisher	Covers	Watch out for
FARS	NHTSA	Every fatal traffic crash, 1975 onward	Deaths within 30 days only; latest year is preliminary
CRSS	NHTSA	Sample of police-reported crashes, 2016 onward	Estimates with error; not comparable to GES
NMVCCS	NHTSA	2005 to 2007 crashes, light vehicles	A “critical reason” is not a cause or fault
LTCCS	FMCSA	2001 to 2003 injury and fatal large-truck crashes	Associated factors are not causes; data over 20 years old
MCMIS	FMCSA	State-reported truck and bus crashes, inspections, carrier census	Preliminary for 22 months; depends on state reporting
SMS / CSA	FMCSA	Carrier percentiles built from MCMIS	Not a safety rating; property carrier percentiles withheld
State systems (e.g. TxDOT CRIS)	State DOTs	All reportable crashes in one state	State thresholds and vehicle definitions
IIHS Fatality Facts, NSC Injury Facts	IIHS; National Safety Council	Compilations and analyses	Definitions can differ from FARS

FARS: the census of deaths

Publisher: NHTSA. What it counts: every fatal motor vehicle traffic crash in the 50 states, the District of Columbia and Puerto Rico since 1975. To qualify, a crash must involve a motor vehicle on a trafficway customarily open to the public and kill someone, in a vehicle or not, within 30 days¹².

What it leaves out: deaths after day 30, crashes on private property not regularly used by the public², and every crash in which nobody died.

Release lag: each year’s data arrive first as an Annual Report File (ARF), which is replaced the following year by a Final File. NHTSA’s large-truck fact sheet for 2024, built on the 2024 ARF, was published in June 2026. It also shows the scale of revision: the 2023 count of people killed in large-truck crashes moved from 5,472 in the ARF to 5,478 in the Final File².

The trap: NHTSA’s FARS-based large-truck tables count any truck over 10,000 pounds gross vehicle weight rating, commercial or not, and exclude buses and motor homes². A FARS “large truck” count and a “commercial vehicle” count from another source measure different fleets.

CRSS: the sample of everything else

Publisher: NHTSA. What it counts: a nationally representative sample of police-reported crashes of every severity, from property damage only to fatal, involving all types of motor vehicles, pedestrians and cyclists³. CRSS replaced the General Estimates System (GES) in 2016².

What it leaves out: crashes no police officer reported.

Release lag: NHTSA’s June 2026 large-truck fact sheet carried CRSS estimates through 2024².

The trap: CRSS numbers are estimates, not counts. FARS deaths are counts². NHTSA warns that GES and CRSS estimates are not comparable because the sample designs differ², so a trend line that runs from 2015 into 2016 splices two different instruments.

NMVCCS and LTCCS: one-time causation studies

Neither is an ongoing data series. Each sent investigators to crash scenes to reconstruct the events just before impact.

NMVCCS (NHTSA, National Motor Vehicle Crash Causation Survey) investigated crashes from July 3, 2005 to December 31, 2007. A weighted sample of 5,470 crashes represents about 2,189,000 crashes nationally⁴. To qualify, a crash had to occur between 6 a.m. and midnight, bring emergency medical services to the scene, and involve a light passenger vehicle that was towed⁵.

LTCCS (FMCSA, Large Truck Crash Causation Study) covered 967 crashes from 2001 to 2003 at 24 sites in 17 states, involving 1,127 large trucks, each crash with at least one death or injury. The weighted estimate is about 141,000 large trucks nationally⁷.

The trap: both studies assigned a “critical reason,” defined as the immediate reason for the pre-crash event that led to the first impact. NHTSA says it is not intended as the cause of the crash or as an assignment of fault⁴. A critical reason is the last link in a chain of events, not a verdict on who caused the crash. That caveat sits underneath the most-quoted figure in road safety: the driver was assigned the critical reason in 94 percent (±2.2%) of NMVCCS crashes⁴. In January 2022 NTSB Chair Jennifer Homendy urged NHTSA to stop using the figure, calling it misleading⁶. In LTCCS the truck was assigned the critical reason in 55 percent of crashes, and in two-vehicle crashes between a large truck and a passenger vehicle the passenger vehicle was assigned it in 56 percent and the truck in 44 percent⁷. The study’s “associated factors,” such as brake problems, coded for 29.4 percent of trucks, record what was present, not what caused the crash⁷. NHTSA also cautions against comparing NMVCCS estimates with other databases⁵. For how these figures are used, see what percentage of crashes are caused by human error and leading causes of large truck crashes.

A critical reason is the last link in a chain of events, not a verdict on who caused the crash.

MCMIS: the carrier file

Publisher: FMCSA, through its Analysis & Information (A&I) Online site. What it counts: crash, census and inspection files for commercial vehicles⁸. States report crashes involving a truck, a bus or a vehicle displaying a hazardous materials placard on a public roadway that result in a death, an injury or a towaway⁸. A&I’s large trucks and buses include commercial trucks over 10,000 pounds, vehicles designed to carry nine or more people, and placarded vehicles⁸.

What it leaves out: crashes states do not report, and crashes with no death, no injury treated away from the scene and no towaway.

Release lag: A&I considers MCMIS crash data preliminary for 22 months⁹. In October 2026 its home page still described 2025 crash numbers as provisional¹⁰.

The trap: an MCMIS crash record is a report that a carrier’s vehicle was involved, not a finding that the carrier was at fault.

SMS percentiles and what Congress withheld

The Safety Measurement System (SMS), part of FMCSA’s Compliance, Safety, Accountability program, scores carriers in seven safety categories and ranks them by percentile within each¹¹¹². FMCSA states that an SMS symbol is not a federal safety rating, and that a carrier is authorized to operate unless it has an Unsatisfactory rating or has been ordered to discontinue operations¹¹.

Section 5223 of the FAST Act of 2015 barred public release of the relative percentile for each category, alerts, analysis of violations, and information on crashes in which the carrier or driver is found not at fault, until the Department’s Inspector General certifies that a list of conditions has been met, including a study of the program’s methodology and fixes for any deficiencies it found. It kept inspection and violation data, out-of-service rates and absolute measures public¹². FMCSA states it has removed alerts and relative percentiles for property carriers from public SMS display¹³.

The trap: a property carrier’s category percentiles are not on the public SMS site. If a story cites one, ask where it came from and when.

State crash databases

Publisher: each state. TxDOT’s Crash Records Information System (CRIS), for one, holds reportable crashes from the Texas Peace Officer’s Crash Report, with summary reports published by June of the following year and a public query tool¹⁴.

What it counts: all reportable crashes under that state’s definition. In Texas that means injury, death or apparent damage of $1,000 to one person’s property¹⁵.

The trap: state vehicle categories do not match the federal ones. TxDOT counts a crash as a commercial motor vehicle crash when the officer marks the CMV box¹⁵. For 2024, TxDOT’s report counted 608 deaths in Texas CMV crashes¹⁶, while NHTSA’s FARS-based fact sheet counted 720 deaths in Texas crashes involving large trucks². See Texas commercial truck crash statistics.

IIHS and NSC: compilations, not sources

IIHS Fatality Facts are annual summaries built on FARS, updated when DOT releases each year’s data¹⁷.

NSC Injury Facts counts motor-vehicle deaths differently. It includes traffic and non-traffic deaths, counts deaths within one year of the crash rather than 30 days, and uses death certificate data from the National Center for Health Statistics. For 2024 it reported 42,789 motor-vehicle deaths, set against NHTSA’s 39,254 traffic deaths¹⁸.

The trap: quoting an NSC total as a FARS number, or the reverse. Both are accurate under their own definitions.

Understanding Liability in Commercial Vehicle Collisions

2026-10-07T00:00:00Z

When two passenger cars collide, responsibility usually stays between the two drivers and their insurers. A truck crash can reach further: to the company that dispatched the truck, the owner of the equipment, the broker that arranged the load, the shipper that loaded it, the maker of a failed part and the agency that maintains the road. Each is judged under its own theory, and state law decides much of the outcome.

This explainer describes how those theories generally work. It is not advice about any particular crash.

The elements of negligence

Most crash claims rest on negligence, which in nearly every state has four parts.

Duty. The defendant owed a duty of reasonable care. Every driver owes one to others on the road, and companies owe duties tied to their own conduct, such as hiring drivers and maintaining equipment.
Breach. The defendant fell short of that standard.
Causation. The breach caused the harm, both in fact and as a matter of law. The second part, proximate cause, asks whether the harm was a foreseeable result.
Damages. Someone suffered a legally recognized loss.

Federal safety rules often enter at the breach stage. States differ on whether violating one proves breach, creates a presumption of negligence or is evidence a jury may weigh. A violation does not prove causation: a driver over the hours-of-service limit may still have been struck by someone running a red light.

The driver

The truck driver is judged by ordinary standards of care, plus duties the federal rules impose on commercial drivers, such as the hours-of-service limits and inspection requirements. A driver can be personally liable, but in serious crashes claims commonly look to the company as well.

The motor carrier: responsibility for the driver

Under respondeat superior, a form of vicarious liability, an employer answers for an employee’s negligence within the scope of employment, even if the employer did nothing wrong itself. The disputes are whether the driver was an employee and whether the driver was on the job at the time. A driver hauling a dispatched load usually is; one running personal errands may not be, and states draw that line differently.

Much of the industry runs on owner-operators who lease their trucks and services to carriers, under contracts that often call the driver an independent contractor. Federal rules complicate that label. The safety regulations define an employee as an individual employed by an employer who directly affects commercial motor vehicle safety in the course of that employment, and the definition expressly includes a commercial driver, “including an independent contractor while in the course of operating a commercial motor vehicle”¹. Federal leasing rules require the lease to give the carrier “exclusive possession, control, and use” of the equipment and to have the carrier “assume complete responsibility for the operation of the equipment” during the lease. The same rule says that requirement is not meant to decide whether the driver is an independent contractor or an employee².

Courts have read these provisions differently. Some hold the carrier whose operating authority the truck runs under responsible to the public for the driver, whatever the contract says; others give the contract or state agency law more weight.

The motor carrier: its own negligence

A carrier can also be liable for its own conduct. Some states limit these direct claims once the carrier admits it is vicariously liable for the driver; others let both proceed.

Negligent hiring and retention. Under Part 391, a commercial driver must, among other requirements, be at least 21, physically qualified, licensed, not disqualified, and road-tested or holding an accepted equivalent³. Within 30 days of a driver’s start, the carrier must request the driver’s motor vehicle record covering the past three years from each licensing state and document an investigation of the driver’s safety performance history with regulated employers over the same period⁴. Those records, medical certificates and annual reviews go into a driver qualification file, generally kept for the length of employment plus three years⁵. The claim asks whether the carrier knew, or would have learned through reasonable care, that the driver was unfit, and kept the driver on the road anyway.

Negligent entrustment. This theory targets handing a vehicle to someone the owner knew or should have known was likely to operate it dangerously, through inexperience, a poor record or impairment. It can reach an equipment owner that is not the driver’s employer.

Negligent supervision. Carriers must require their drivers to follow the federal driver rules⁶, and may not schedule runs that can be completed only by exceeding speed limits⁷. These claims often ask whether a carrier monitored hours of service, acted on violations and complaints, or set schedules that pushed drivers past legal limits.

Negligent maintenance. Part 396 requires carriers to systematically inspect, repair and maintain their vehicles and to keep parts and accessories “in safe and proper operating condition at all times”⁸. Defects on a driver’s inspection report that are likely to affect safety must be repaired before the vehicle runs again, with the carrier certifying the repair or that none was needed⁹. See How Commercial Truck Maintenance Failures Lead to Crashes.

All four theories depend on records that carriers must keep only for set periods. Evidence After a Commercial Vehicle Crash lists those periods, and The Federal Motor Carrier Safety Regulations: A Reader’s Map shows where each rule sits.

Brokers

A freight broker arranges, for compensation, the transportation of property by an authorized motor carrier¹⁰. Injured parties have sued brokers for negligently selecting unsafe carriers. Brokers answered that the Federal Aviation Administration Authorization Act (FAAAA) preempts those claims. The statute bars states from enforcing laws “related to a price, route, or service” of a motor carrier or broker with respect to transporting property, but says the bar “shall not restrict the safety regulatory authority of a State with respect to motor vehicles”¹¹. The federal circuits split over whether that safety exception covers negligent-selection claims¹².

On May 14, 2026, the Supreme Court resolved the split. In Montgomery v. Caribe Transport II, LLC, a unanimous Court held that a claim that one company negligently hired another to transport goods falls within the safety exception, because requiring a broker to use ordinary care in choosing a carrier concerns the trucks that will haul the goods¹².

The ruling settles less than it might seem. The Court assumed, without deciding, that the claim would otherwise be preempted. A separate FAAAA provision on brokers’ intrastate services has no safety exception, a mismatch the Court acknowledged before holding that the text of the provision before it controls¹²¹¹. Whether a broker was negligent, what checks a reasonable broker must make and whether the choice caused the crash remain questions of state law and fact. A concurring opinion stressed that brokers who act reasonably and hire reputable carriers should be able to defend these suits, and that proximate cause limits their exposure¹².

Shippers and loaders

A shipper tenders property to a carrier for transport¹. Drivers and carriers have their own federal duty to see that cargo is properly distributed and secured, and to recheck it on the road¹³, and federal lease rules require the lease to say who is responsible for loading². Many courts place the duty to secure a load on the carrier, but a shipper that loaded the trailer may answer for a defect the driver could not have found through reasonable inspection. Hazardous materials shippers carry additional federal duties.

Manufacturers and parts suppliers

When a brake component, tire, coupling or steering part fails, the maker of the truck, trailer or part may face a product liability claim for a design defect, manufacturing defect or failure to warn. States differ on strict liability and defenses. Separating a defective part from a badly maintained one is often the central fight, and it depends on preserved physical evidence.

Public road agencies

Road design, a missing sign, a malfunctioning signal or an unrepaired hazard can contribute to a crash. Governments are generally immune from suit except as they consent, and state tort claims acts waive that immunity only in part.

Texas shows the common features. Its Tort Claims Act requires notice of a claim within six months of the incident, and city charters may set shorter periods. It caps damages for bodily injury or death at $250,000 per person and $500,000 per occurrence for the state and for cities, and at $100,000 and $300,000 for other units of local government¹⁴. It excludes claims based on discretionary decisions, and claims over a missing or malfunctioning sign or signal unless the agency failed to correct it within a reasonable time after notice¹⁴. Other states set different caps, deadlines and exceptions.

How states divide fault

When more than one party is at fault, including the injured person, state law decides how responsibility is shared.

Pure comparative negligence. Recovery is reduced by the plaintiff’s share of fault, whatever its size. A plaintiff found 70 percent at fault can still recover 30 percent of the damages.

Modified comparative negligence. Recovery is reduced by the plaintiff’s share but barred entirely once that share reaches a threshold¹⁵. Under a 50 percent bar, a plaintiff who is as much at fault as the defendant recovers nothing. Under a 51 percent bar, recovery ends only when the plaintiff’s share exceeds 50 percent. Texas uses the second version: a claimant more than 50 percent responsible recovers nothing, and otherwise damages are reduced by the claimant’s percentage¹⁶. Texas also limits each defendant to its own share of the damages unless that defendant is more than 50 percent responsible or a narrow exception applies¹⁶.

Pure contributory negligence. Alabama, Maryland, North Carolina, Virginia and the District of Columbia keep the older rule: a plaintiff whose own negligence contributed to the harm, even slightly, is generally barred from recovering¹⁵¹⁷. Doctrines such as last clear chance can soften it, and the District of Columbia has carved out an exception for pedestrians, bicyclists and other nonmotorized road users¹⁵.

When the crash, the carrier and the court sit in different states, which state’s law applies is its own question, and it can decide the case.

Insurance as the practical backstop

Liability decides who should pay. Insurance often decides what can be collected. Interstate for-hire carriers of nonhazardous property in vehicles of 10,001 pounds or more must carry at least $750,000 in public liability coverage, and certain hazardous cargo requires $1,000,000 or $5,000,000¹⁸. Those levels have not been raised since 1985¹⁸. The concurring opinion in Montgomery observed that the statute mandates minimum insurance coverage for trucking companies but not for brokers¹². The figures, and the debate over raising them, are covered in Federal Minimum Insurance for Motor Carriers.

Leading Causes of Large Truck Crashes

2026-10-07T00:00:00Z

Ask why large trucks crash and most answers lead back to a single federal study. The Large Truck Crash Causation Study (LTCCS) remains the most detailed investigation of serious truck crashes the United States has published, and its figures still turn up in FMCSA’s own driver guidance and in much of what is written about truck crashes. They are also misquoted constantly, usually by treating a list of conditions present at a crash as a list of causes. What follows is what the study measured, what it found, and how far its findings reach.

What the study was

FMCSA and NHTSA ran the LTCCS together, collecting data on crashes from 2001 to 2003 at 24 sites in 17 states. The sample was 967 crashes involving 1,127 large trucks, each with at least one death or injury. Weighted, it represents about 141,000 large trucks in fatal and injury crashes nationally¹.

The depth sets it apart. Each crash was worked by a researcher and a state truck inspector, who interviewed drivers, passengers and witnesses, inspected the trucks, contacted carriers, and reviewed police, hospital and coroner records¹. Police crash reports, the basis for most crash statistics, cannot match that.

The analysis rests on three coded items¹:

The pre-crash event: the action or event that put the vehicles on a course that made the collision unavoidable.
The “critical reason”: the immediate reason for that event. One was coded per crash, and it was always assigned to the vehicle involved in the event.
Associated factors: any of roughly 1,000 conditions or circumstances present at the time of the crash, recorded whether or not they contributed.

The “critical reason” is not a finding of fault and not a legal cause. It identifies the failure closest in time to the point of no return. NHTSA states the same limit for its own passenger-vehicle research, where the “critical reason” “is not intended to be interpreted as the cause of the crash”³. Our piece on human error in car crashes covers how that companion study has been misused.

The truck was not always the problem

Across all LTCCS crashes, the truck was assigned the “critical reason” in 55 percent of cases¹. The split changes in the crashes the public most often pictures. In two-vehicle crashes between a large truck and a passenger vehicle, the passenger vehicle was assigned the “critical reason” in 56 percent and the truck in 44 percent¹.

That finding undercuts two opposite assumptions: that the truck is presumptively at fault in a truck-car crash, and that car drivers cause most truck crashes. The data supports neither. The immediate failure was the car driver’s in a large share of collisions and the truck driver’s in a large share. Which applies is a question of the facts of each crash, not of the vehicle class. For drivers of both trucks and cars, the report found recognition and decision failures the most common¹.

Driver, vehicle, environment

When the truck was assigned the “critical reason”, the study then asked where the failure lay¹.

Where the truck’s “critical reason” lay	Share
Driver	87.2%
Vehicle	10.1%
Environment	2.3%
Unknown	0.3%

The driver category breaks down further. Measured against every truck assigned the “critical reason”, decision errors made up 38.0 percent: driving too fast for conditions, misjudging other vehicles’ speed, following too closely. Recognition errors made up 28.4 percent: inattention and distraction. Non-performance accounted for 11.6 percent, a driver who fell asleep or was disabled by a heart attack, seizure or other impairment. Performance errors were 9.2 percent: freezing, overcompensating, poor directional control¹.

The vehicle share, about one truck in ten, deserves more attention than it gets. The report says vehicle failures on trucks were concentrated in three areas: braking capacity, tire or wheel failure, and cargo shift¹. Each is a maintenance or loading problem a carrier controls. Our explainer on truck maintenance failures covers how they develop.

The associated factors, read correctly

The LTCCS coded associated factors for every truck in the sample, including trucks not assigned the “critical reason”. The most frequent, as a share of the 141,000 weighted trucks¹:

Associated factor (trucks)	Share of trucks
Brake problems	29.4%
Traffic flow interruption	28.0%
Prescription drug use	26.3%
Traveling too fast for conditions	22.9%
Unfamiliar with roadway	21.6%
Roadway-related factors	20.5%
Required to stop before crash	19.8%
Over-the-counter drug use	17.3%
Weather-related factors	14.1%
Inadequate surveillance	13.2%
Fatigue	13.0%
Work-related pressure	9.2%
Illegal maneuver	9.1%
Inattention	8.5%
External distraction	8.0%
Following too closely	4.9%

The table is routinely misquoted as “brakes cause 29 percent of truck crashes” or “prescription drugs cause a quarter of them.” Neither claim is supported. A truck with an out-of-adjustment brake can be rear-ended at a red light, and the brake is still coded.

The study’s analysis brief offers a better tool. For each factor it calculated a relative risk: how often trucks with the factor were assigned the “critical reason”, compared with trucks without it². That separates conditions that merely travel with crashes from conditions that track with being the vehicle that failed.

Brake problems: relative risk 2.7.
Traveling too fast for conditions: 7.7.
Fatigue: 8.0.
Inadequate surveillance: 9.3.
Inattention: 17.1.
Following too close: 22.6.
Illegal maneuver: 26.4.
Cargo shift: 56.3, though it was coded for only 4 percent of trucks.

Prescription drug use, third on the frequency list, does not appear in the relative risk table at all. The brief reports no statistical difference in how often trucks with and without that factor were assigned the “critical reason”, and the same was true of traffic flow interruption and being required to stop before the crash². The study does not support treating those three frequent factors as signs that the truck failed.

The two lists rank the factors very differently. Brake problems top the frequency table and carry a modest relative risk. Following too closely sits near the bottom of the frequency table and carries one of the highest. The brief makes a point worth keeping: “Crash reconstruction experts rarely conclude that crashes are the result of a single factor”². Our analysis of truck driver fatigue looks at one of these factors in depth.

Where the study stops

Four limits shape any use of LTCCS data.

It is old. The crashes date from 2001 to 2003. Since then, ELDs have replaced most paper logs, the hours-of-service rules have changed more than once, and collision mitigation systems and in-cab cameras have spread through many fleets. Patterns in the data may hold up; specific percentages may not.

It covers only serious crashes. Every case involved an injury or death. Property-damage-only crashes may follow different patterns.

It codes, it does not adjudicate. The “critical reason” is a research classification made with the information the team could gather. It is not a finding of negligence and was never meant to be one.

Nothing has replaced it yet. FMCSA’s Crash Causal Factors Program is building a successor. Its first study, the Heavy-Duty Truck Study, covers fatal crashes involving Class 7 and 8 trucks, those rated at 26,001 pounds or more, and targets a nationally representative sample of 2,000 fatal crashes from about 30 states over two years⁴⁵. FMCSA’s program page, last updated in September 2026, says the agency is preparing states for data collection, projected for 2026 to 2029, with a final report and anonymized public crash database in 2030⁴. Our field guide to U.S. crash data covers the census and sample datasets that fill some of the gap in the meantime.

Reading the data from the cab, the office and the scene

For carriers. The LTCCS places most truck-side failures with the driver, and the factors with the highest relative risk are behaviors: following distance, surveillance, attention, legal maneuvers, speed for conditions. Hiring, training, coaching and monitoring all bear on them. Fatigue, at a relative risk of 8.0, ties back to dispatch and scheduling as well as to the driver. On the vehicle side, the truck-assigned failures clustered in brakes, tires and wheels, and shifting cargo, and every one of those is an inspection, maintenance or loading item.

For drivers. Following too closely appeared for only 4.9 percent of trucks, but when it appeared the truck was far more likely to be the vehicle assigned the “critical reason”. Speed for conditions is the other standout. Both are decisions made in the cab.

For investigators. Start with the event that made the collision unavoidable and work backward, but do not stop at the first failure. A crash coded to the car driver can still involve a truck with brakes out of adjustment. A crash coded to the truck driver’s decision can still trace to a schedule that left no room to slow down. Associated factors are leads to run down, not conclusions, and the hours-of-service record, engine and telematics data, maintenance file and inspection history are where they get tested. How those records bear on responsibility is covered in our explainer on liability in commercial vehicle collisions. The rules differ by state and by the facts of each case.

Deer Strikes and Auto Insurance: Why Comp Coverage Usually Applies

2026-10-07T00:00:00Z

A deer strike is one of the few crashes where the coverage question is often simpler than the repair. In most standard auto policies, damage from hitting an animal is paid under comp coverage (other-than-collision), not under collision coverage. The National Association of Insurance Commissioners says so directly, and adds the catch: comp is an optional part of the policy.¹

Two parts of the policy

Collision coverage pays to repair or replace your car after it hits another vehicle or an object. Comp pays for damage from causes other than a collision, such as theft, fire, flood, vandalism and, in most policies, animals.² Insurers file a deer strike under comp even though, physically, the car collided with something. The Texas Department of Insurance lists “hitting an animal” among the losses most policies pay, provided the driver carries comp.²

The deductible still applies

A comp claim carries its own deductible, which may differ from the collision deductible on the same policy. The Texas Department of Insurance notes that drivers pay a deductible on both collision and comp claims.² If the repair estimate is close to the deductible, filing a claim may not be worth it. The Iowa Insurance Division suggests filing when damages exceed the deductible.³

Liability-only policies

Liability coverage pays for damage you cause to other people and their property. It does not pay to fix your own car. NAIC says that a driver who has only collision or liability coverage will not be covered for damage from hitting an animal.¹ The Iowa Insurance Division gives the same warning.³ Drivers who own their cars outright often drop comp and collision to save on premiums; a deer strike is when that choice shows. A lender usually requires both coverages while a car is financed.²

The swerve problem

Here is where the coverage lines matter. If you hit the deer, the claim usually goes under comp. If you swerve, miss the deer and hit a tree, a guardrail or another car, you have collided with an object, and the claim usually becomes a collision claim, with the collision deductible and, depending on the insurer, possible effects on your premium. Swerving also tends to make the crash more dangerous, which is why NAIC warns that drivers who swerve “could lose control and hit a tree or veer into oncoming traffic.”¹

The difference in coverage can also tempt drivers to say they hit a deer when they did not. Virginia transportation researchers noted that some policies cover deer crashes but not crashes with fixed objects such as a guardrail or a tree, and that false deer claims would inflate insurance-based counts.⁴ A claim that does not match the damage invites an investigation.

Documenting the strike

NAIC advises photographing the vehicle damage, the roadway and any injuries.¹ Note the time and place and get contact details for any witnesses. Fur, hair or blood on the bumper or grille supports an animal claim. If the crash involved injuries, or if state law or the insurer requires it, file a police report. Rules on reporting differ by state; Virginia’s are covered in our guide to deer collisions in Virginia.

Glass and rental cars

Glass. Windshields often crack in deer strikes. Glass damage is commonly handled under comp; the Massachusetts Division of Insurance, for one, says glass and windshield coverage in that state is provided by comp, and that glass deductibles are permitted.⁵ Some insurers offer separate glass terms, so check the declarations page.

Rental cars. A rental while your car is in the shop is usually a separate, optional coverage, often called rental reimbursement. The Texas Department of Insurance describes it as paying “for you to rent a car if yours is stolen or being repaired after an accident.”² Without it, the rental may be out of pocket.

Policies and states vary

Everything above describes how standard personal auto policies commonly work. Coverage names, deductibles, glass terms and claim handling differ by insurer, by policy and by state, and endorsements can change any of them. Read your own declarations page, and ask your insurer or your state’s insurance department when something is unclear. Nothing here is legal or insurance advice about a specific claim.

BTT Road & Legal

How Commercial Truck Maintenance Failures Lead to Crashes

Brakes come first

The failure modes that matter most

What Part 396 requires

Roadside inspections and out-of-service orders

Why the records matter after a crash

What Data Is Stored in a Commercial Truck's Electronic Control Module?

What the module is and why heavy trucks have one

What the records commonly include

How the data is downloaded

How the data gets lost

How ECM data differs from ELD, telematics and camera records

How reconstructionists use it

Commercial Truck Driver Fatigue: Statistics and Safety Risks

What fatigue does to a driver

What the Large Truck Crash Causation Study found

Why police crash data undercount fatigue

Sleep apnea and the medical certificate

Schedule pressure, detention and parking

What the records show, and what they miss

Texas Commercial Truck Crash Statistics

The sources

Statewide, by year

Counties with the most CMV crashes

By road class

By time of day

One state, three death counts

Methods

What Texas counts as a commercial motor vehicle crash

What counts as a reportable crash

Serious injuries

Known limits

Pedestrians, Cyclists and the Shape of the Road

Speed sets the stakes

Wide roads and long crossings

Darkness

The engineer’s menu

How this fits the Safe System Approach

What Percentage of Car Accidents Are Caused by Human Error?

Where the number comes from

What “critical reason” means

The driver errors, broken down

What the number does not mean

The NTSB chair’s objection

How truck crash research compares

The systems view

How to cite this figure accurately

How Crash Reconstruction Works

The physics

Conservation of momentum

Crush energy

Skid to stop

The data and the measurements

Event data recorders

Mapping the scene

Simulation

Where each method runs out

Hours-of-Service Rules Explained

Who the rules cover

The limits side by side

One driver’s day, hour by hour

The weekly limit and the 34-hour restart

The sleeper berth split

Exceptions that change the arithmetic

How the rules are enforced

What hours records show after a crash

State rules for intrastate trucking

The Federal Motor Carrier Safety Regulations: A Reader's Map

Who the rules reach

The parts, one by one

How states carry the rules to intrastate carriers

Where the text lives

The out-of-service criteria are a separate document

Federal Minimum Insurance for Motor Carriers: The $750,000 Floor

The schedule

Passenger carriers

What the MCS-90 does

Unchanged since 1985

Brokers and freight forwarders: $75,000, for a different purpose