Every crash your fleet is involved in leaves a short window to collect the facts that will decide how the claim, the safety record and any lawsuit turn out. A disciplined investigation helps you meet federal recordkeeping and testing rules, gives your insurer what it needs to defend you, and shows you what to change so the same crash does not happen twice. This guide walks through the regulatory baseline, the first 72 hours, a root-cause review, and where insurance typically responds.
Know what counts as a DOT-recordable accident
Under the Federal Motor Carrier Safety Regulations, an "accident" is an occurrence involving a commercial motor vehicle on a highway that results in a fatality, an injury to a person who immediately receives medical treatment away from the scene, or disabling damage to a vehicle that requires it to be towed. Boarding or leaving a stationary vehicle and loading or unloading cargo are excluded.
The injury prong turns on the phrase "medical treatment," and FMCSA guidance draws practical lines:
- Observation or a checkup only is not medical treatment.
- X-rays and other imaging, such as CT scans, are diagnostic and are not treated as medical treatment.
- Receiving prescription medication, or a prescription, counts as medical treatment.
A pending change to watch
In May 2025 FMCSA proposed writing its "medical treatment" guidance into the regulation itself. As of this writing it remains a proposal, so continue to apply the current definition and guidance, and check for a final rule before you change your procedures.
Investigate non-recordable incidents too. Backing strikes, dock damage, mirror clips and near misses rarely reach the accident register, but they are often the early warning signs of the crash that will. Our guide to preventing backing accidents covers one of the most common of these.
Meet the recordkeeping and testing rules
The accident register
Motor carriers must keep an accident register for three years after the date of each accident. Each entry records the date, the city or town and state, the driver's name, the number of injuries and fatalities, and whether hazardous materials other than the vehicle's own fuel were released. Copies of accident reports required by a state, another government body or an insurer belong with the register. Carriers must also make these records available to authorized investigators and give reasonable assistance in any accident investigation.
Post-accident drug and alcohol testing
| Crash outcome | Driver cited for a moving violation? | Test required? |
|---|---|---|
| Human fatality | Not relevant | Yes, each surviving driver performing safety-sensitive functions |
| Injury treated immediately away from the scene | Yes | Yes |
| Vehicle towed due to disabling damage | Yes | Yes |
| Injury or tow-away, no citation | No | No DOT test required |
Tests are due as soon as practicable. If an alcohol test is not done within 2 hours, document why; if it is not done within 8 hours, stop trying and document the reasons. For controlled substances, stop attempting after 32 hours and document why. Drivers must remain available for testing unless they need medical care or leave to get help, and drivers should carry your post-accident instructions before they drive. Our DOT drug and alcohol testing guide covers the rest of the program.
The first 72 hours: preserve the evidence
Evidence disappears quickly. Vehicles are repaired, video is overwritten and memories change. Build a short, written checklist and train dispatch and drivers on it before you need it. Our article on what drivers must do at the scene covers the driver's side; the company-side tasks look like this:
- Confirm safety and testing. Make sure injured people are cared for, then decide immediately whether a post-accident test is required and send the driver for it.
- Notify your insurer or broker. Report the same day. Most policies require prompt notice, and early notice lets the carrier send an adjuster or investigator while the scene still exists.
- Lock down electronic data. Download or protect dash-camera video, telematics events, ELD records and, where available, engine control module data before it is overwritten.
- Photograph and measure. Vehicle positions, damage, skid marks, signage, sight lines, weather and lighting. Wide shots first, then detail.
- Collect statements. Get the driver's written account as soon as practical, plus witness names and contact details. Record facts, not conclusions.
- Hold the equipment. Do not repair a vehicle involved in a serious crash until your insurer agrees. Keep any failed parts.
- Get the police report. Note the report number at the scene and request a copy as soon as it is available; you will need it for any preventability challenge.
Do not admit fault or promise payment
Drivers and managers should be courteous and cooperative, but questions of liability belong to your insurer and, where needed, defense counsel. Statements made at the scene or on social media can be used later.
Find the root cause, not just the at-fault driver
A good investigation asks why the crash happened and what would have prevented it, not only who was to blame. Use a consistent format for every review:
- Reconstruct the sequence. Line up the timeline from video, telematics, ELD data, dispatch messages and statements.
- Look at the driver factors. Hours worked and rest in the prior days, schedule pressure, training history, prior events and how long the driver has run this route or equipment.
- Look at the vehicle. Inspection and maintenance records, defects reported on prior inspection reports and whether repairs were completed.
- Look at the system. Dispatch practices, delivery windows, route planning, policy gaps and whether coaching after earlier events actually happened.
- Decide preventability internally. Ask what a reasonable, alert professional driver could have done differently. This is separate from legal fault.
- Assign corrective actions with owners and dates. Coaching, retraining, a policy change, an equipment fix or a schedule change, then confirm it was done.
The same root-cause method works across operations; our article on incident investigation explains it in more depth, and telematics programs can supply much of the data.
Use FMCSA's preventability and data review programs
Crashes appear in FMCSA's Safety Measurement System whether or not your driver caused them. Through the Crash Preventability Determination Program, a carrier or driver can ask FMCSA to review eligible crashes. For crashes on or after December 1, 2024, there are 21 eligible crash types, including being struck in the rear, being struck by a wrong-way driver, being legally stopped or parked when struck, and crashes where video shows the sequence of events.
- Requests are filed as a Request for Data Review through the DataQs system, and a police accident report must be included.
- Any additional documents FMCSA requests must be provided within 14 calendar days, or the crash is marked "Undecided."
- Crashes found Not Preventable are excluded from the Crash Indicator BASIC measure and percentile and are noted on the driver's Pre-Employment Screening Program report.
- FMCSA cannot review crashes more than five years old.
In October 2026 FMCSA reported that all states had implemented a reformed DataQs review process, under which officers cannot decide challenges to their own work and states face set timelines for initial, reconsideration and final decisions. Dash-camera video and a complete file make these requests far stronger. See understanding and improving your CSA scores for how crashes affect your profile.
Where insurance typically responds, and where gaps appear
| Exposure | Coverage that typically responds | Common gap to check |
|---|---|---|
| Injury or damage to others | Commercial auto liability, then umbrella or excess | Limits that are low relative to contract requirements or the size of your operation |
| Damage to your truck or trailer | Auto physical damage | Deductibles, stated values that lag replacement cost, and non-owned or interchange trailers |
| Freight in your care | Motor truck cargo | Commodity exclusions, unattended vehicle conditions, and reefer breakdown terms |
| Your injured driver | Workers' compensation | Owner-operators who are not covered under any policy |
| Employees driving personal or rented vehicles | Hired and non-owned auto liability | Not added to the policy at all |
Forms, exclusions and conditions vary by carrier and policy, so review your actual policy wording. Two conditions matter in almost every crash: the duty to give prompt notice, and the duty to cooperate with the insurer's investigation. A thorough internal file supports both. It also supports your position at renewal, when underwriters look at loss runs alongside what you did after each loss. Our truck insurance and commercial auto insurance pages describe these coverages in more detail.
When to call your broker
- Immediately after any crash with injuries, a fatality, a tow-away or a hazmat release.
- When you receive a demand letter, a lawsuit or a request to preserve evidence.
- When a crash reveals a coverage question, such as an unlisted driver, a borrowed trailer or a vehicle used outside its usual radius.
- Before renewal, to present corrective actions and preventability findings with your loss history.
As a broker, we compare options across the market and shape coverage around how your fleet actually runs. We can also help you build an investigation checklist that fits your operation.
Sources
- Cornell LII — 49 CFR 382.303, Post-accident testing
- eCFR — 49 CFR 390.15, Assistance in investigations and special studies
- FMCSA — Guidance on medical treatment for accident register purposes
- FMCSA — Accident reporting: modification to the definition of medical treatment (proposed rule)
- FMCSA — Crash Preventability Determination Program fact sheet
- CCJ — FMCSA's DataQs reforms officially in effect