The consumption of fuel by vehicles is a function of several factors. Some of the important ones are: motor characteristics, gear characteristics, average velocity and velocity change frequency. Driving proficiency is a factor which may have a considerable influence on the fuel usage efficiency and can be improved by proper training. The vehicle’s maintenance level also affects fuel consumption and may be improved. Fuel grade and the usage of proper fuel can also have an affect on the amount and cost of fuel consumed by a vehicle. For supervising the vehicle fuel usage efficiency, it is essential to have a constant survey of the amount of fuel consumed in respect of the distance traveled.
The measurement of fuel consumption can provide information not only with regard to technical aspects of the vehicle, usage and maintenance. It may provide information also as regards possible fraudulent activity such as unauthorized usage or fuel theft. German patent application disclosure DE19941970A1 the contents of which are incorporated herein by reference, describes a method is for recording on board a vehicle the fuel consumption and the distance traveled, thereby enabling for example, to compute the average consumption.