tachograph
/ˈtækəˌɡræf/
noun
- A device in a vehicle that records its speed, distance traveled, and driving time, often used in trucks and buses to monitor driver hours.
- Modern tachographs use digital technology to record and store driving information.
- Police officers examined the tachograph data after the accident to determine the vehicle's speed.
- The truck driver checked the tachograph to ensure he hadn't exceeded his allowed driving hours.