The laboratory and test bench testing of vehicle components and assemblies is followed by in-vehicle tests, which culminate in the validation of the vehicle as a whole. Road testing shifts from initial trials on dedicated proving grounds to public roadways. Standard drive cycles, e.g., stop-and-go in city traffic, are completed as well as high-speed runs or tests under various road conditions. In many cases, to verify performance under extreme conditions of temperature and altitude, vehicles are subjected to driving tests in Arctic regions, desert areas, or high mountain ranges.
Calibration engineers adjust and optimize their assemblies onboard the vehicle, e.g., with regard to driving characteristics. In addition, thresholds of diagnostic functions are verified against environmental parameters.
New vehicle models are subjected to fleet endurance trials during both pilot and production series, clocking several hundred thousand kilometers per vehicle. The data obtained in these trials flows back into the testing and development departments and contributes to ongoing vehicle optimization.