CAPACITY AND LEVEL OF SERVICE AT TWO-WAY STOP CONTROLLED INTERSECTIONS: COMPARISON OF BRITISH AND U.S. METHODS. HIGHWAY CAPACITY AND LEVEL OF SERVICE. PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON HIGHWAY CAPACITY, KARLSRUHE, GERMANY, 24-27 JULY 1991

This study was conducted for the purpose of comparing the U.S. (1985 Highway Capacity Manual) and British methods for capacity and level of service estimation at unsignalized intersections. Data were collected in 15 minute intervals at five different intersection sites. A total of 14 different intervals of data were obtained. Each intersection was made up of a major road and a minor road with only vehicles on the minor road being required to stop at the intersection. Thus, vehicles on the minor road were forced to stop and wait for acceptable gaps in the major road traffic before executing their next movement. The Highway Capacity Manual (HCM) uses a method based on gap acceptance theory to estimate capacities for these types of intersections. In Britain, on the other hand, an empirical, regression based model is used. For the data collected in this study, the British method easily outperformed the HCM method. Capacity estimates given by the British method agreed much more closely with measured delays and observed operating conditions than estimates given by the HCM method.