Abstract
Studies of accidents on rural highways and motorways in Germany have shown that roadway and traffic conditions which affect the quality of traffic flow - i.e. which affect operating speed, freedom of manoeuvre, driver comfort and other traffic characteristics which in turn affect convenience - do not necessarily have a similar effect on accidents. Roadway and traffic characteristics which may make driving more comfortable can have a negative influence on safety; and roadway and traffic conditions which have no perceptible effect on driver comfort can have a considerable influence on accident risk.