MODEL OF FUEL ECONOMY WITH APPLICATIONS TO DRIVING CYCLES AND TRAFFIC MANAGEMENT

Fuel consumption by a vehicle is expressed in terms of a few vehicle characteristics and summary characteristics of any trip. This simple physical model can readily be adapted to any vehicle or combination of vehicles. The needed data for U.S. vehicles are in the public domain. Numerical results in the applications discussed are for an average U.S. car. One potential application is in modifying driving cycles to more accurately reflect actual driving behavior. The model shows that instead of a second-by-second velocity pattern being needed, fuel consumption depends on a small number of speed characteristics that summarize a trip: average speed, an average peak speed, braking time, stop time, and number of stops per unit distance. A second application concerns traffic management and fuel consumption. Average speed is the main determinant of fuel use. Attempted top speed of free-flow velocity is also an important determinant. Together, these driving characteristics enable a reasonable estimate of fuel consumption for planning purposes. For example, measures that increase traffic speed (up to about 50 mph) while decreasing maximum speed improve fuel economy. In these applications and others that are discussed, the coefficients are fundamental characteristics of the vehicles involved.