The distinction between different levels in road networks can be explained from the point of view of both the network users and public authorities. A hierarchic network structure makes it possible to meet the variety of user wishes and at the same time to meet the constraints determined by the authorities, such as the financial budget or environmental constraints. Using a simple network structure, it can be shown that for hierarchic network structures a scale factor 3 is plausible. The factor 3 is in accordance with values that have been found using empirical data. The scale factor 3 implies that a subnetwork of a higher level should have a road spacing that is three times as large as the road spacing of the lower level network and that the average speed should be 50% to 67% higher. (A)
Abstract