Abstract: A digital tachograph system includes a vehicle unit operative to detect vehicle performance characteristics such as vehicle speed, elapsed trip distance, engine rpm, total engine revolutions, total fuel consumption, rate of fuel consumption and the like as a function of time. The forgoing vehicle performance characteristic data is displayed in the vehicle unit and is stored in a data memory located therein. A fixed base unit includes a central computer system for processing vehicle performance data, storing the data in a memory file and for reading out the vehicle performance data in the form of a printout, graph plot, CRT display or the like. The vehicle performance data may be transferred from the vehicle unit to a field terminal which connects to the central computer system either by means of a cable connection by directly interconnecting said portable memory unit or by radio transmission means.

Abstract: An electronic multi-mode vehicle performance control system selectively provides a digital display of odometer, tachometer, speedometer readings as well as other vehicle performance parameters while avoiding the disadvantages of mechanical systems which are subject to frequent breakdown. Provision is made to signal the operator of the vehicle when a preselected maximum vehicle velocity or engine rpm is being exceeded and furthermore to signal the operator when the engine rpm drops below a preset minimum level with the consequent danger of engine stall. Other vehicle parameters such as total elapsed engine revolutions is also displayed. Also provided are digital speed limit setting means for presetting the desirable vehicle and engine speed limits.