FUEL EFFICIENCY AND OTHER OBJECTIVES IN TRAFFIC SYSTEM MANAGEMENT

Abstract

This paper discusses the objective of reducing vehicle fuel consumption in urban conditions in relation to other traffic management objectives. The discussion is based on the tactical issues related to these objectives aimed at finding a practical compromise. An elemental model of fuel consumption (pollutant emission, cost etc) is described in detail. Examples are given of isolated and co-ordinated signal control. The objective of reducing pollutant emissions is treated in a similar manner, although there is a conflict between fuel consumption and pollutant emission reduction objectives. A detailed discussion of the selection of models for predicting fuel consumption is given. The elemental model is preferred because of its clarity, simplicity and relevance to existing traffic modelling techniques. Possible errors in the model such as the effect of stops, the effect of multiple stops and slowdowns, the use of stop-line delay instead of idling. The results from the examples given in the paper show that fuel consumption reductions of about 5 to 10 per cent could be expected from optimum traffic signal control. (TRRL)