The objective of this study is to investigate the frequencies of encounters between vehicles of particular widths and their effects on the quality of flow. The investigations have been performed by different methods. The first step was a statistical analysis of the widths of the vehicles registered in Germany. In addition a theoretical formula for the number of encounters has been derived. The frequency of encounters was also investigated by video observations at 25 streets of various categories. Other video evaluations analysed delays and velocities which occur at encounters. The results were used in a computer simulation program. This estimated the frequencies of encounters between vehicles of any width as well as the effects on the quality of flow. Speed-flow diagrams were established for the allowed maximum velocities of 50 km/h and 80 km/h for different street widths and different proportions of heavy vehicle traffic. The results are presented and discussed.
Abstract