1. SUMMARYFor the simulation of driving road- and offroad-vehicles a mathematical model as well as a program have been developed, which allows the prediction of the driving performances, driving time and speed, fuel consumption, exhaust emissions, loading of the drive line and strain on the driver when the vehicle runs on prescribed routes. The driving simulation takes into account engine, tire, gearbox, and general vehicle data, height and outline profiles of the route, visibility, permissible transverse acceleration and wheel or exhaust braking. The aim of the simulation calculations is to find the optimum overall economy for given operating conditions by coordinating the individual elements of the total system of engine-transmission-vehicle. Not only can vehicles be optimized, but existing vehicles can also be easily compared and assessed.One great advantage of computer simulation is the possibility of accurately recreating operating conditions, which in traffic are of course influenced by chance traffic conditions and also by the most diverse driver characteristics.