Fuel consumption accounts for a large proportion of the operating costs of large capacity haul trucks used in open cut mines. Computer simulation of truck performance offers an excellent and cost effective method to assess the means by which operating costs can be reduced.A computer program called ‘HAUL’ developed at the University of Melbourne, Australia is described. In its various versions, HAUL is a multipurpose model designed to assess the performance and fuel consumption of diesel-electric haul trucks with different configurations and under various operating conditions. The program can yield information on fuel consumption, power demand and driving cycle (speed/time profile) for any actual or synthesized vehicle configuration. The input data include, among other things, diesel engine fuel map, record of complete round trip and grades, transmission efficiency and rolling resistance.