Truck crash evidence disappears in 30 days The letter that keeps it alive.
A carrier has to keep a driver's logs for six months and the ELD backup for six months. The truck goes back to work inside a week. A preservation letter names each item, and the first month decides the case.
On this page
The records that decide a truck case are kept on a schedule, and the schedule is short: federal rules require a motor carrier, meaning the trucking company, to keep a driver’s records of duty status, the hours log, for six months and a back-up copy of the electronic logging device data for six months. Nothing requires it to keep the engine data, the camera footage, or the truck itself in the condition it was in. A preservation letter, sent in the first days, is what stops the clean-up.
Three words that decide a truck case
What the trucking company must keep
These are minimum retention periods from the Federal Motor Carrier Safety Regulations, as printed in the 2025 annual edition of the Code of Federal Regulations published on govinfo.gov. They are floors: a carrier may keep records longer, and a well run one does, but it is not required to.
| Record | Minimum retention | Regulation |
|---|---|---|
| Driver’s records of duty status and supporting documents | 6 months from the date of receipt | 49 CFR 395.8(k)(1) |
| Back-up copy of ELD records | 6 months, on a separate device | 49 CFR 395.22(i)(1) |
| Vehicle inspection, repair, and maintenance records | 1 year where the vehicle is housed, plus 6 months after it leaves the carrier’s control | 49 CFR 396.3(b), (c) |
| Accident register and copies of accident reports | 3 years after the date of each accident | 49 CFR 390.15(b) |
| Driver qualification file | While employed, plus 3 years after | 49 CFR 391.51(c) |
| Alcohol test at 0.02 or higher, verified positive drug test, refusals | 5 years | 49 CFR 382.401(b)(1) |
| Negative and cancelled drug tests, alcohol below 0.02 | 1 year | 49 CFR 382.401(b)(3) |
The sources, in order: section 395.8(k)(1) sets the six months for records of duty status; section 395.22(i)(1) requires a six month back-up copy of the ELD records on a separate device; section 396.3 sets the maintenance record rule; section 390.15(b) requires the three year accident register including copies of accident reports required by states or insurers; section 391.51(c) covers the driver qualification file; and section 382.401(b) sets the testing record schedule.
The driver's drug test happens within hours
Post-accident testing is decided before anyone hires a lawyer. Under 49 CFR 382.303, the employer must test a surviving driver for alcohol and controlled substances as soon as practicable after a qualifying crash, which includes any accident involving a fatality, and accidents with an injury requiring immediate treatment away from the scene or a vehicle towed away where the driver is cited.
Then the windows close. If the alcohol test is not administered within two hours, the employer has to make a record of why. If it is not administered within eight hours, the employer must stop trying. For controlled substances the limit is 32 hours. Whether that testing happened, and what the carrier wrote down about why it did not, is fixed by the end of the second day.
The evidence nobody has to keep
What is missing from the table matters as much as what is in it. There is no federal minimum retention period in those sections for the engine control module download, for forward or inward facing camera video, for telematics and GPS breadcrumbs, the truck’s transmitted location and performance data, for dispatch and messaging records, or for the tractor and trailer themselves. Those are the items that answer the questions a jury cares about: how fast, how hard the braking, how long since the last stop, and what the driver was told about the schedule.
In the ordinary course, a damaged tractor is repaired and returned to service, a leased trailer goes back to the leasing company, a camera system overwrites on its own cycle, and an ECM keeps recording over what it holds as the truck runs. None of that requires anyone to act in bad faith. It only requires that nobody was told to stop.
What a preservation letter has to demand
A preservation letter, sometimes called a spoliation letter, goes to the motor carrier, its insurer, the driver, and whoever physically holds the vehicle, usually a tow yard. It asks them to preserve, not to produce, and it is specific enough that nobody can later say they did not understand what was wanted. Specificity is the point.
- The tractor and trailer in their post-collision condition, including all onboard devices, and notice before any repair, sale, or release of either unit.
- The engine control module and any event data recorder data, downloaded by an agreed protocol with our representative present, before the vehicle is moved back into service.
- All records of duty status, supporting documents, and ELD data for the driver, including but not limited to the 30 days before the collision.
- Forward facing, inward facing, and side camera video, telematics and GPS data, and all dispatch, messaging, and load documents for the trip.
- Inspection, repair, and maintenance records for both units, driver vehicle inspection reports, and the driver qualification file.
- Post-accident drug and alcohol testing records, including any record explaining why a test was not administered.
- The accident register entry and all accident reports required by any state, agency, or insurer.
The letter is sent by a method that proves receipt, and it goes out in days rather than weeks. In our practice this is the first substantive thing that happens in a truck file, before any demand and often before the client is out of the hospital. The scene side of the same problem, photographs and witnesses, is in our post on the five steps to take after a crash.
Why the letter matters at trial
California juries can be instructed on destroyed evidence. CACI No. 204, Willful Suppression of Evidence, reads in full: “You may consider whether one party intentionally concealed or destroyed evidence. If you decide that a party did so, you may decide that the evidence would have been unfavorable to that party.” The Directions for Use, the notes published with the instruction, say it should be given only if there is evidence of suppression.
That is the reason the letter exists. A carrier that overwrites camera video before anyone asked has an ordinary business explanation. A carrier that overwrites it after a certified letter identified it by name has a different conversation ahead of it. The letter does not create evidence. It creates the record of notice that turns a loss into a question.
When the truck rules are different
- The regulations above are the federal ones. They apply to carriers subject to the Federal Motor Carrier Safety Regulations. A purely local operation, a rental box truck, or a government vehicle can raise different questions about which rules govern, and that is a question for the file rather than a web page.
- A public agency truck changes the deadline. A city, county, or state vehicle puts you on the six month written claim deadline under Government Code section 911.2, not the two year one.
- The truck is already repaired. The case is not over. Repair invoices, parts orders, and the shop’s photographs become the record of what the damage was, and the carrier’s own maintenance file has to be produced anyway.
- Nothing was destroyed. Most carriers preserve what they are told to preserve, and their adjusters still handle the claim the way our post on dealing with insurance after an accident describes. The letter is inexpensive insurance against the one that does not, and it also fixes the scope of what exists before anyone argues about it.
- The deadline for the case is longer than the deadline for the evidence. You have two years to sue under Code of Civil Procedure section 335.1. The logs may be gone in six months. Those are different clocks and only one of them is forgiving.
What proof did in one truck case
The truck case in our results came out of a freeway sideswipe by a semi-truck, where the client suffered a concussion and the first offer was $100,000. The case settled on the eve of trial for $6,300,000. Truck files turn on what can be proved about the carrier and the driver, and that proof exists in records that have a shelf life.
- First offer
$100,000Recovered$6,300,000
Prior results do not guarantee a similar outcome. Every case depends on its own facts, injuries, and insurance coverage. Amounts shown are gross recoveries before attorney's fees, costs, and medical liens.
All case resultsQuestions people ask after a truck crash
How long does a trucking company have to keep the driver’s logs?
What is a preservation letter?
What is spoliation, and what happens if evidence is destroyed?
Is the truck’s black box data automatically saved?
Was the driver drug tested after the crash?
How soon do I need a lawyer in a truck case?
How to stop the evidence from disappearing
The logs and the ELD back-up have a six month floor, maintenance records a year, and the truck itself has none at all. What stops the loss is a specific, early letter to everyone holding a piece of it, sent by a method that proves receipt, followed by an inspection of the vehicle before it is repaired.
If a truck hit you last week, the useful next step today is to write down every identifier you have: the carrier name on the door, the USDOT number, the trailer number, the tow company, and the responding agency. That list is what a preservation letter is built from. Our Los Angeles truck accident lawyer page explains how these cases are put together, our guide to what a truck accident lawyer does covers the rest of the work, and there is no fee unless we recover.
