Most of the evidence in an 18-wheeler claim is held by the trucking company, not by the injured person: the engine computer, the electronic log, the driver’s personnel file and the repair records. Federal rules make the carrier keep some of those records for as little as three months, so the practical task is to learn what exists and to ask in writing that it be kept before a retention period runs out.
The short version
- Four sets of records matter most. They are the truck’s electronic data, the driver’s hours records, the driver qualification file, and the inspection and maintenance records.
- Retention periods are short. A daily vehicle inspection report is kept for three months (49 CFR 396.11), and a log with its supporting documents for six (49 CFR 395.8).
- The retention sections in this post do not list a truck’s engine data. NHTSA’s event data recorder rule, by its stated weight limits, covers vehicles of 8,500 pounds or less gross rating and 5,500 pounds or less unloaded (49 CFR 563.3).
- Lost evidence rarely wins by itself. In a 2015 per curiam opinion the Texas Supreme Court limited when a jury may be told to presume destroyed evidence was unfavorable.
- Ask for preservation early and specifically. A written request that names each item is the usual first step, and the carrier’s reply tells you what still exists; what a claim may be worth is on the truck settlement page.
What counts as key evidence in an 18-wheeler accident claim?
It falls into three groups: what the truck recorded, what the trucking company is required to keep, and what outsiders captured, such as police, witnesses and other drivers’ cameras. A car crash has the third group almost alone. A truck crash adds the first two, and the opposing side controls them.
The firm’s 18-wheeler practice page describes the case type. A motor carrier must keep an accident register for three years and make accident records available to FMCSA and to state or local enforcement representatives (49 CFR 390.15), but those duties run to the government. An injured person has to ask. How the whole claim differs from a car claim is in the overview of truck claims, the work a lawyer does from intake to resolution is in the start-to-finish description, and what to photograph and write down at the scene is in the companion list of first steps; this post stays with the records and data themselves.
What does the truck itself record?
A tractor’s engine control module can keep vehicle speed, engine speed and other readings around a triggering event, and an electronic logging device stores time, location, engine hours and miles. Some trucks also carry forward-facing cameras and fleet-tracking units.
The National Transportation Safety Board’s report on a December 2022 rear-end crash near Williamsburg, Virginia (Highway Investigation Report HIR-24-05, 12 August 2024) shows what such data can look like. It says the engine control module “is capable of capturing vehicle speed, engine speed, and other parameters during triggered events,” and that the recovered event data covered 120 seconds at one-second intervals. The data showed speeds of 65 to 70 mph, cruise control engaged and no braking before impact. The report notes that the systems did not record steering angle.
Two limits apply. First, the federal event data recorder standard in 49 CFR 563.3 applies to equipped vehicles built on or after 1 September 2012 with a gross vehicle weight rating of 8,500 pounds or less and an unloaded weight of 5,500 pounds or less, a class far below a loaded tractor-trailer. Read by those weights, it does not reach a heavy truck; that is a reading, not a ruling. Second, an electronic logging device does not record everything: the federal rule lists date, time, location, engine hours, vehicle miles and identification data, with an automatic entry at least hourly while the truck moves (49 CFR 395.26). Engineers and trucking-safety witnesses read this data; see the experts a truck case calls.
How do electronic logs help prove a truck crash, and when can they mislead?
They show when the truck moved and who was logged in, and can be checked against fuel receipts, tolls and dispatch messages. They can also be wrong: the NTSB found a carrier that had created fictitious driver accounts in its logging system, so a clean-looking log is a starting point, not a conclusion.
A carrier must hold a driver’s record of duty status, with supporting documents, for at least six months after receiving it (49 CFR 395.8(k)), and must hold a six-month back-up copy of electronic logging device records on a separate device (49 CFR 395.22(i)). In the Williamsburg investigation, the NTSB found that the carrier “created fictitious driver accounts” in its logging system, enabling drivers to work beyond federal hours limits, and said that tracking data entry in the software could deter false entries. That was one carrier in one report. The limits themselves and how a violation is shown are in the separate guide to the Part 395 driving limits.
Which company files can show a driver or truck problem?
The driver qualification file, the daily vehicle inspection reports, the annual inspection report and the maintenance history. Each is required by a specific federal section, and each can show whether the carrier hired, trained, inspected and repaired as the rules say.
The driver qualification file under 49 CFR 391.51 must include the driver’s employment application, the motor vehicle record from the licensing authority, the road test certificate or its accepted equivalent, a note on the annual review of the driving record and the medical examiner’s certificate. The medical side is explained in our post on driver medical fitness, and testing records in proving drug use by truck drivers.
On the vehicle side, a driver writes up each vehicle after the day’s work, covering brakes, tires, steering, lights, couplings and other listed parts, but need not prepare a report when nothing is wrong (49 CFR 396.11). So a day with no report does not prove a defect-free truck. The carrier’s own maintenance records under 49 CFR 396.3 must show the inspection and repair dates and nature. How brake and tire records connect to specific crash types is covered in why a truck fails to stop and tire failures on trucks.
How long must a trucking company keep its records?
It depends on the record: three months for a driver’s daily vehicle inspection report, six months for hours-of-service records, fourteen months for a periodic inspection report, up to five years for some drug and alcohol records, and the length of employment plus three years for a driver qualification file.
| Record | Minimum period stated in the rule | Section |
|---|---|---|
| Driver vehicle inspection report, repair certification and review | Three months after the report is prepared | 396.11(a)(4) |
| Driver’s record of duty status and supporting documents | At least six months after receipt | 395.8(k)(1) |
| Back-up copy of electronic logging device records | 6 months, on a separate device | 395.22(i)(1) |
| Inspection, repair and maintenance records | 1 year at the place the vehicle is housed or maintained, plus 6 months once the vehicle is out of the carrier’s control | 396.3(c) |
| Periodic inspection report | Fourteen months from the date of the report | 396.21(b)(1) |
| Accident register | 3 years after the date of each accident | 390.15(b) |
| Driver qualification file | As long as the driver is employed and three years after; some items may be removed three years after execution | 391.51(c), (d) |
| Drug and alcohol testing records | 5 years (positive results, refusals, program records), 2 years (collection process), 1 year (negative results) | 382.401(b) |
The periodic inspection rule and the drug and alcohol retention rule are the sources for those two periods. None of these sections lists engine-computer data or camera video as a record with its own retention period, which is why those depend on the carrier’s own settings and on how quickly someone asks. The deadline to sue is separate, generally two years in Texas for personal injury (Civil Practice and Remedies Code § 16.003(a); for timing, see the length of a Texas injury case), so a record can expire well before a case must be filed.
What did the Texas Supreme Court say about lost evidence?
In a 2015 per curiam opinion, the court said a jury may be told to presume destroyed evidence was unfavorable only if the party that lost the evidence acted with intent to conceal it, or acted negligently and caused the other side to be irreparably deprived of any meaningful ability to present a claim or defense. Having other evidence available weighed against giving the instruction.
The case, Wackenhut Corp. v. Gutierrez, No. 12-0136 (Tex. Feb. 6, 2015), involved a charter bus with four cameras that recorded only while the bus was running and looped over their recordings after 168 hours. One camera may have captured the impact, and that recording was lost. The trial court found negligent spoliation and told the jury it could presume the video was unfavorable to the bus company. The Supreme Court reversed and ordered a new trial.
The court applied the framework from Brookshire Bros., Ltd. v. Aldridge, 438 S.W.3d 9 (Tex. 2014), which it summarized this way: an instruction is allowed only if the party (1) acted with intent to conceal discoverable evidence, or (2) acted negligently and caused the other party to be irreparably deprived of any meaningful ability to present a claim or defense. On the second point, the court listed the evidence still available, including both drivers’ testimony, an eyewitness, the police report, photographs and medical records, and held that “in light of the abundance of available evidence” the plaintiff was not irreparably deprived.
A lost recording does not automatically become a presumption in your favor, so the other evidence must be gathered too; shared-fault arguments make that more important. The judge, not the jury, decides whether spoliation occurred and what remedy fits.
How do you ask a trucking company to preserve its evidence?
In writing, as early as possible, and by naming each item: the engine module data, electronic log records, any camera video, the driver’s file, inspection and maintenance records, dispatch messages and the truck and trailer themselves. A general request to keep “all records” gives the carrier room to argue it did not know what mattered.
A preservation letter is not a court order; what it does is record the date the carrier was told what to keep. A useful letter identifies the crash by date, place and vehicles, asks that the truck not be repaired or returned to service before its data is downloaded, and lists the record types in the table above. For an out-of-state carrier, see choosing counsel for an out-of-state truck; the USDOT number lookup is in the first-steps list. Who should receive one depends on the parties a truck claim can reach.
The carrier’s insurer may take over the response, which is why what not to tell the carrier’s adjuster and the coverage behind an 18-wheeler are separate topics; gross-negligence claims also turn on what records show. A preservation request can be raised through the contact page; why to speak with counsel before the adjuster and the personal injury overview give the wider picture.
What evidence can an injured person collect without a lawyer?
Photographs of the vehicles, the road and any skid marks, the names and phone numbers of witnesses, your medical records and bills (who gets to see them is a separate question), and the police report. Other drivers’ dashboard video can matter too: in a lawsuit reported in January 2026, a camera in a third vehicle recorded the crash.
The Texas Department of Insurance tells drivers to photograph the vehicles, license plates, damage, street signs and road angles, to talk to witnesses and get names and phone numbers, and to write down the location, time, weather and what happened (TDI, “Were you in a wreck?”, last updated 24 September 2025). Which photographs help is in the guide to crash photos, and why witnesses matter in the note on witness statements; a death changes who may sue (wrongful death claims).
A January 2026 Houston Public Media story (7 January) covers a lawsuit, filed by representatives of four women’s estates, over a November 2025 18-wheeler crash near Dalhart in the Panhandle; the plaintiffs sued H-E-B, two transportation companies and the driver, and a dashboard camera video from a third vehicle was released to media by the plaintiffs’ attorneys. The suit’s claims are allegations; the point here is only that a camera in an unrelated vehicle can fill gaps the truck’s own data cannot.
The police file is a second outside source. TxDOT keeps the officer’s crash report, but it says it holds the report alone and that subpoenas for dash cam video, field notes, photographs and other on-scene information go to the investigating agency, not to TxDOT (TxDOT page on crash records). The steps for ordering the report are in ordering the crash report.
Frequently asked questions
What is black box data in a truck accident case?
It is the information stored by the truck’s engine control module, such as speed, engine speed and braking around a triggering event, sometimes with an electronic log and camera video. In the NTSB’s Williamsburg report, it showed 120 seconds of speed data at one-second intervals and no braking before impact.
How does the black box help a truck accident case?
It can show how fast the truck was going and whether the driver braked, which can confirm or contradict the driver’s account. It does not record everything: in the NTSB report, the systems did not capture steering angle, so engineers combine it with video and physical evidence.
What evidence do I need to file a truck accident claim?
No single item is required to start a claim. The usual core is the police report, your medical records and bills, photographs and witness names. Company records are requested through counsel and, in a lawsuit, by formal demand.
What evidence matters most in a truck accident case?
It varies with how the crash happened, so no ranking holds for every case. In the Texas Supreme Court’s 2015 opinion, the court weighed driver testimony, an eyewitness, the police report, photographs and medical records together and held the plaintiff was not irreparably deprived of any meaningful ability to present his claim.
How can I preserve evidence after a truck accident?
Keep your photographs, the other driver’s information, your medical records and bills, and any messages about the crash. For the truck’s data and the carrier’s files, a written preservation request naming each item should be sent promptly, because some records are required to be kept only three to six months.
Can a trucking company discard a driver’s logs after six months?
The federal minimum for a driver’s log and the supporting documents is six months from receipt (49 CFR 395.8(k)). The rule sets the shortest period and does not forbid keeping the records longer, so an earlier written request is what keeps them from being routinely discarded.
About the authors
Sam A. Maida, Jr.
Owner and Managing Attorney
Sam A. Maida, Jr. has represented injured Texans in the greater Houston area since the firm opened in 1993.
State Bar of TexasAvvoMartindale-HubbellLawLinkThatCarHitMeLinkedIn
Bernard G. Johnson III
Litigation Managing Attorney
Bernard G. Johnson III is a board certified trial lawyer licensed in Texas since 1996 and a graduate of South Texas College of Law.