Quick Answer
Electronic logging device (ELD) data, dashcam and inward-facing camera footage, dispatch and route records, the driver’s qualification file, post-crash drug-and-alcohol test results, vehicle maintenance and inspection logs, GPS and telematics data, and the California Highway Patrol commercial vehicle crash report. Most of this is routinely overwritten within 30-90 days unless an attorney sends a litigation hold letter immediately.
Reviewed by Daryoosh Khashayar, ABOTA Member, founder and managing partner of Khashayar Law Group — Last updated May 2026.
The strongest predictor of recovery in a commercial truck case is the evidence that survives the first 30 days after the crash. Federal regulations require commercial carriers to retain certain records for fixed periods — ELD data for six months under 49 CFR §395.8, driver qualification files for as long as the driver is employed plus three years under 49 CFR §391.51 — but carriers routinely destroy records the moment the retention period expires, and dashcam footage is on a 30-90 day rolling buffer that overwrites automatically.
A formal litigation hold letter, sent to the trucking company and its insurer within the first week of the case, freezes those records. Courts in California impose sanctions for spoliation of evidence (destruction after notice of pending litigation), which gives the letter teeth. Daryoosh Khashayar sends litigation hold letters within days of retainer on every truck case.
In our $5 million truck-and-scooter case, dashcam footage and post-crash drug-and-alcohol test results preserved in the first 72 hours were the deciding evidence. The California Highway Patrol’s initial report placed 100% of fault on our client; the preserved evidence reversed that determination and produced a policy-limits recovery.
An Electronic Logging Device automatically records a commercial truck driver’s hours of service: when the engine is running, when the truck is moving, when the driver is on duty, and when the driver is off duty. ELDs replaced paper logs in 2017 and are mandatory under 49 CFR §395.20.
ELD data is the single most important evidence in any fatigue-related truck crash. It reveals whether the driver was over the 11-hour daily driving limit, the 14-hour on-duty window, or the 70-hour 8-day rolling limit. Hours-of-service violations are negligence per se in California courts. ELD records are retained for six months under federal rules — after that, they can be overwritten unless preserved.
Most fleet dashcam systems retain footage on a 30-90 day rolling buffer that automatically overwrites. Some carriers retain only “event-triggered” footage (hard braking, swerving, collisions) and discard routine driving footage within hours. A litigation hold letter sent within the first 7-14 days is what stops the overwrite cycle and freezes the data.
Inward-facing cab cameras (showing the driver) are increasingly common and are powerful evidence of distracted driving, fatigue, and phone use. They are subject to the same retention buffer.
Under 49 CFR §382.303, post-crash drug-and-alcohol testing is mandatory for the driver of any commercial vehicle involved in a crash where: (a) anyone receives medical treatment away from the scene, (b) a vehicle is towed from the scene, or (c) there is a fatality. The driver must take an alcohol test within 8 hours and a drug test within 32 hours.
The test results are evidence in the civil case. Refusal to test is treated as a positive test under FMCSA rules.
A litigation hold letter (also called a preservation letter or spoliation letter) is a formal notice to the trucking company, the driver, the insurer, and any other potential defendant that legal action is anticipated and that all records related to the crash must be preserved. The letter typically demands preservation of every category of evidence listed above, plus emails, text messages, and internal communications about the driver and the crash.
Once the letter is received, intentional destruction of listed records is spoliation of evidence and triggers court-imposed sanctions in California, including adverse inference instructions to the jury.
This FAQ relates to our Truck Accidents practice. To send a litigation hold letter before evidence disappears, call (858) 509-1550 — the consultation is free, and the first 30 days set the trajectory of the case.