Recent developments in calculation methods for unsignalized intersections in west Germany

This paper gives a survey of the development of calculation methods for unsignalized intersections in Germany. First of all, some comments and critical notes on the German guideline published in 1972 and the procedures adopted in the HCM 1985 are given. Moreover, the present state of the art, which comprises the calculation of capacities and queues with stationary and partially non-stationary traffic streams by merely mathematical methods and by simulation models, is described. For future practical application in Germany, both a simple calculation method and a practicable simulation model are planned. However, with respect to the correct consideration of impedance effects of traffic streams at intersections, some theoretical questions still have to be discussed up till the introduction of a new guideline.