Findings are presented from a preliminary analysis of the manner in which the elevation profile of highway pavements affects vehicular resistance to motion as a result of the energy lost in: the visco-elastic tire, and the hydraulic damper used to control oscillations of the 'sprung' and 'unsprung' masses. The findings indicate the relative importance of these two vehicle elements in constituting energy sinks in highway transport, as a function of road roughness and vehicle velocity. Further, the additional resistance to motion caused by the requirement for a motor vehicle to be steered and to sideslip in order to negotiate a curved section of road is identified and discussed, in relationship to the observation that the actual fuel consumption of motor vehicles is greater than that estimated on the basis of laboratory measurements. Language: en