Before federal ELD mandates, hours-of-service violations were proven through paper logs that drivers — under pressure from dispatchers — routinely falsified. Investigators would interview, subpoena fuel receipts, and triangulate. Slow and contested.
Now, every commercial truck above a certain weight class carries an ELD that records when the engine is running, when the truck is moving, and when the driver has logged on or off duty. The data is timestamped, encrypted, and (under federal regulations) must be preserved for at least six months.
What ELDs reveal
- Whether the driver was over hours-of-service limits at the time of the crash
- Whether the carrier's dispatch records align with the driver's logs
- Whether the driver was experiencing fatigue patterns visible in micro-stops and speed variation
- Whether the truck was speeding or following too closely (when paired with telematics)
The preservation problem
ELD data is overwritten. Carriers are required to preserve it after a serious crash, but compliance varies. The single most important thing a plaintiff's attorney does in a trucking case is send a federal preservation letter within hours of taking the case — putting the carrier on formal notice that data must be saved. Failure to preserve becomes a spoliation argument that often shifts cases dramatically in the plaintiff's favor.
If you've been hit by a commercial truck, the 72 hours after the crash matter more than almost anything that happens in the next 18 months.
— DiLeonardo & Shaw · Trucking