The models presented for predicting fuel consumption and emissions for vehicles driven on the road provide the means for averaging and storing results obtained from vehicle tests usually carried out at an emissions test facility to standard and non-standard-drive schedules. For hot start fuel usage and emissions rates the models, in descending order of temporal or spatial resolving capability, include: transient engine mapping (a new model), steady state engine mapping, vehicle mapping, power demand, modal or elemental, lumped parameter (PKE-v) and travel time variants. The engine mapping model is shown to be able to predict instantaneous on-road fuel consumption with good precision (±3ml) for one vehicle over a selected 3.3 km stretch of road. Its emissions rate predicting ability is less satisfactory. When link-by-link fuel is needed the 6 coefficient PKE-v model performs well (R = 0.994). The models can also be applied to transfer emissions and fuel consumption from one drive cycle to another.