Trip computer
A trip computer is a computer fitted to some cars; most modern trip computers record, calculate, and display the distance travelled, the average speed, the average fuel consumption, and real-time fuel consumption. The first, mechanical trip computers, such as the Halda Speedpilot, produced by a Swedish taximeter manufacturer, were made in the 1950s as car accessories to enable the driver to maintain a given time schedule, particularly useful in rallying.