Abstract
In order to estimate emission factors for road vehicles especially by means of mechanistic simulation models, but even in some cases by measurements on chassis dynamometers, information about air resistance coefficients (CD) must be available. The conclusion from this literature survey is that there are sufficient data for cars, if manufacturers¦ data is accepted as representative. For other vehicle types the available CD-data is not enough to estimate representative values of CD and consequently representative emission factors cannot be estimated. (Author/publisher)