The effects of traffic congestion on fuel consumption

Traffic congestion results in additional travel time and vehicle operating costs to road users. It is important to be able to quantify these effects more accurately in order to undertake economic appraisals of road improvement projects. This paper outlines a methodology developed to predict the additional fuel consumption due to traffic congestion. It was found that driver behaviour could be represented through the standard deviation of acceleration, i.e. the acceleration noise. As traffic congestion increases, so does the traffic-induced acceleration noise. Experiments were conducted to measure acceleration noise with a number of different vehicle types and drivers under varying levels of congestion and on high-and low-standard roads in New Zealand, Malaysia and India. A Monte-Carlo simulation model was developed which used the acceleration noise in conjunction with a mechanistic fuel model to predict the fuel consumption of vehicles at different levels of congestion. The model was found to give consistent and reasonable results when applied to different classes of roads.