Abstract
Increasing environmental awareness has forced the German government to introduce periodic exhaust gas testing for all motor vehicles in road transportation. First, effective techniques for various serial tests and inspections of vehicles with Otto and diesel engines will be described. Then various testing and measurement methods and their technical backgrounds will be explained. Through evaluations and objection rates, the ecological benefits of exhaust gas testing will be compared to the overall economic costs. Finally, an outlook on future engine development and the corresponding adaptation of the test methods will be provided.