Motor vehicle fuel consumption

This is a summary report and overview of a project designed to assist in motor vehicle fuel conservation programmes. The project findings are presented in seven separate papers. Three major thrusts were investigated: (1) seven fuel consumption models were evaluated using Perth traffic data; the results suggest that models using pke and pip are superior to those preferred by traffic engineers. (2) In order to upgrade the main roads department traffic model it was shown that there is no obvious relationship between fuel consumption and road type on a junction free basis; as well the elements were calculated for merging traffic on freeway entrances from a simple model. (3) Some traffic management strategies were evaluated including: (a) the relationship between speed limits and fuel consumption showing an optimum speed of 55 km/h and progressive losses in efficiency above this speed. (b) coordinated traffic lights gave significant fuel and time savings when the major flows were considered but in the total system only 1 to 3 per cent savings were found. (C) easing congestion was found through a survey and some bus data to have significant potential negative impacts on public transport patronage and hence have an overall effect of increasing fuel consumption. This was confirmed in an examination of energy use patterns by region within Perth where locational factors were found to override any advantages in improved fuel efficiency through freer flowing traffic (a).