Publication
The simple average travel speed model of fuel consumption is widely used but the interpretation of its parameters and its areas of use have not been well understood. By deriving aggregate (but detailed) fuel consumption functions from a new instantaneous fuel consumption function, the coefficient of the average speed term can be shown to equal the idle fuel rate and the constant term can be shown to be related to the fuel required to provide tractive force to the vehicle. Thus, the constant term accounts for drag, inertia and grade components of fuel consumption and is influenced by vehicle