Abstract
Traffic engineers are more and more interested in the emergence and spread of exhaust gas from road traffic, especially in densely populated urban areas. The spread of exhaust gas in the vicinity of the road cannot be sufficiently predicted up to now, particularly since there are no generally acknowledged calculation methods. At the Ruhr University, Bochum, wind tunnel experiments have been carried out for several years, and it has been possible to observe the spread of exhaust gas in a model on a scale of 1:200. In the course of these experiments, the laws of aerodynamics have to be taken into account. The air turbulences caused by the traffic flow have a decisive influence, too.