What Is a Truck's Black Box?
Every commercial truck built after 2000 contains an Electronic Control Module (ECM), also called a black box. Unlike airplane black boxes, truck ECMs are designed primarily for vehicle performance monitoring — but they capture critical accident data as a byproduct.
What the Black Box Records
In the 30 seconds before a crash, the ECM records: vehicle speed (accurate to within 1 mph), throttle position, brake application timing, engine RPM, seatbelt status, and cruise control status. This data often tells a story very different from what the truck driver claims happened.
The Preservation Problem
Trucking companies are legally required to preserve ECM data after an accident — but only if they receive proper legal notice. Without that notice, data can be overwritten within 30 days during normal operations. Our attorneys file preservation letters the same day we take your case.
How We Use ECM Data in Court
In a recent Arizona case, a truck driver claimed he was going 55 mph and braked immediately upon seeing our client's vehicle. The ECM showed 71 mph and no brake application until 0.4 seconds before impact. This single piece of evidence turned a disputed liability case into a $2.1M settlement.