Samenvatting
The aim of the studies and surveys carried out in traffic engineering is as a rule to find out the present condition in the following aspects: a) Traffic volume; b) Traffic flow composition; c) Directions of traffic streams; d) Elements characterizing the traffic flow; e) Economic characteristics of traffic. Some of the surveys carried out may follow a number of such aspects simultaneously. In order to evaluate these surveys different kinds of graphs can be used. This article summarizes the basic types of surveys and the graphs used in their evaluation.