A collision with an 80,000-pound truck is not a bigger version of a car crash — it is a different kind of case. Among the reasons is a quiet stream of electronic data that records what the driver and the truck were doing. That data can decide the case, but only if it survives long enough to be used.
Most commercial trucks are required to run an electronic logging device, or ELD. It exists to track a driver's hours behind the wheel. For an injured person and their lawyer, it is one of the most valuable records a trucking case can produce — and one of the most perishable.
What an ELD actually records
An ELD connects to the truck's engine and automatically logs the driver's duty status and driving time. At its core, it is designed to enforce the federal limits on how long a driver may operate before resting. In practice it can help establish:
- Hours of service. When the driver was driving, on duty, off duty, or resting — and whether they exceeded the limits meant to prevent fatigue.
- Drive time before the crash. A long, unbroken stretch behind the wheel speaks directly to fatigue, one of the recurring dangers in trucking.
- Movement and timing. Engine-linked data can corroborate when the truck was moving, helping reconstruct the sequence of events.
Read alongside other records — the driver's logs, dispatch instructions, and the truck's maintenance history — ELD data helps answer a central question: was this driver pushed, or pushing, past the point of safe operation?
Fatigue is hard to prove with testimony alone — a tired driver rarely admits it. ELD data can show it objectively, in numbers that are difficult to argue with.
The problem: this evidence does not wait
ELD and related records are not kept forever. The regulations require carriers to retain certain records for a limited period, and data can be overwritten, cycled out, or simply lost on routine schedules measured in months — sometimes less for the most granular data. A truck damaged in a crash may be repaired or sold. Dashcam footage, if it exists, can be among the first things to disappear.
The result is a hard reality: the most important evidence in a trucking case is often deleting itself while the injured person is still in the hospital. By the time a claim is filed months later, the window may have closed.
What "speed matters" means in practice
This is why experienced trucking representation moves immediately on preservation. The key early step is a spoliation letter — a formal notice to the carrier demanding that it preserve specific categories of evidence and warning against their destruction. A well-drafted letter typically asks the company to hold:
- ELD and hours-of-service data.
- The driver's logs, qualification file, and any disciplinary history.
- Dispatch and communication records around the trip.
- Truck maintenance and inspection records.
- Any onboard camera or telematics footage.
- The vehicle itself, in its post-collision condition.
Sending that notice early does two things. It increases the chance the data still exists when it is formally requested, and it puts the carrier on record — so that if evidence is later destroyed despite the warning, that destruction itself becomes part of the story.
In a serious trucking case, the clock starts at the moment of impact — not at the moment a lawsuit is filed. The sooner preservation is demanded, the more of the truth survives.
If you've been hit by a commercial truck
You do not need to understand the regulations to protect yourself. What helps most is acting quickly: get medical care, keep everything from the scene, and speak with a lawyer who handles trucking cases before key evidence ages out. The difference between a case built on the carrier's data and one built on guesswork often comes down to how fast someone moved to preserve it.