Abstract
Highways can sometimes be a barrier. When they fit well into the planological and social environment they will cause few problems. Part of their action as a barrier is determined by the difficulty of crossing the road. Important factors are the environment, traffic engineering, traffic control, and the density and speed of traffic. The traffic concentration can be influenced by the selection of the opening of the infrastructure. It is necessary to take all these aspects into account before the decision is made on where and how to design a road.