Vehicle energy consumption and emissions can be predicted via drive cycle simulation. The complexity of existing and future vehicles necessitates the use of a simulation tool to aid in this work. A library of modules has been written that represents elements of powertrains found in conventional, electric and hybrid vehicles. The library makes use of the SIMULINK simulation environment. It allows users to quickly and easily develop complex models. These simulation models can be used to predict a vehicle's performance, fuel consumption, electrical consumption and emissions.