(gr. tachos - speed + grapho - to write)
It is a measuring device combining speedometer and clock. Tachograph registers: the distance traveled, speed, and driver activity (time driving, resting). Some types also register engine`s RPM.
Analog tachograph register it`s reading on
waxed paper disc.
Analog tachographs are easy to be cheated on therefore are replaced by digital units.
It is a European Union requirement that all the trucks and buses have tachographs. I wonder if any of You have used such thing, or is any company using it. Rumors are that TMC installs these devices on their trucks.