A SIMPLIFIED APPROACH TO CALCULATION OF FUEL CONSUMPTION IN URBAN TRAFFIC SYSTEMS

A linear relation between fuel consumed per unit distance and the reciprocal of the average trip speed, which was determined from earlier experiments, is used to estimate the effect on overall fuel consumption in an urban system due to changes in average traffic speed brought about by, for example, traffic engineering improvements. With the aid of a relation between average traffic speed and traffic flow reported in the literature, the effect on fuel consumption due to changes in the amount of traffic in a fixed urban traffic system is estimated. Also, the effect of adding one more vehicle to, or removing one vehicle from, an already congested urban traffic system is evaluated. This result is used to calculate the overall fuel penalty to the traffic system when one driver elects to make a trip during a period of high, rather than low, congestion. The overall fuel penalty is the sum of the penalty incurred by the individual driver choosing to make the trip and the penalty incurred by all other users of the system due to the increase in congestion caused by the additional vehicle. Procedures for estimating these separate penalties are given.(a) /TRRL/