Abstract
It is argued that traffic experts have to support the road authorities in their efforts to design and build safe roads and to eliminate those that are not safe, for example in the Netherlands. They need an instrument for checking and controlling the infrastructure with regard to safety, suggesting measures to be taken and using experiences with comparable measures. For this purpose, a model was developed consisting of the elementary triangle: (1) the 'function' of a road, (2) the 'design' to be derived from that; and (3) the resulting 'use' referring to the traffic behaviour of road users on roads.