Samenvatting
In many traffic stream models the role of the fundamental diagram is of great importance. Using measurements on queues at roadblocks it is possible to determine parameters of the level of service F region of the diagram:viz. saturation flow, mean speed at saturation flow, jam concentration and the speed of the starting wave. A description of the method and some results of data from one-lane traffic are presented. Special attention is given to the problem of the influence of lorries.