speedometer vs tachograph

speedometer

noun
  • An instrument located within the dashboard of a vehicle that measures and indicates the current speed of the vehicle. 

  • Such a device incorporating an odometer. 

tachograph

noun
  • A device that records the distance and time traveled by a vehicle (especially a truck or coach), used to check the drivers' working time. 

How often have the words speedometer and tachograph occurred in a corpus of books? (source: Google Ngram Viewer )