ETYM Greek tachos speed + -graph.
A tachometer that produces a graphical record of its readings; used to record the speed and duration of trips in a motor vehicle.
Instrument for recording speed of rotation.
Instrument installed in vehicle recording distance traveled, number and length of stops, speeds, and similar data.
Combined speedometer and clock that records a vehicle's speed (on a small card disc, magnetic disc, or tape) and the length of time the vehicle is moving or stationary. It is used to monitor a truck driver's working hours.