Abstract
Emperical research carried out in Detroit, Michigan, in an effort to a better utilizing of the capacity of an urban freeway with the aid of an information- and control system is described. The traffic situation was improved with an effective dosage to ramps and exits and the application of an information system consisting of interchangeable indications about the route with the shortest journey time at a given moment. The usefulness of a warning system for intermissions in traffic flow was tested. The relation between these studies and future research in this field in Germany is mentioned.