This paper presents the results of a high hazard location analysis for several cities in the state of Michigan, USA, and shows how the rate-quality control technique provides a reasonable method of analysis. Traffic crash histories were analysed for the cities of Grand Rapids (1988-90) and Muskegon (1990-91). In both cities, the crash frequency and crash rate methods were used initially, to derive a list of high crash locations, from which the ten most dangerous locations were identified using the rate-quality control method. The critical traffic crash rates at intersections were obtained for both cities, using fine groupings of the different types of roadway situations. Determination of the critical crash rate, based on a 95% confidence level, for example, enables safety analysts to identify locations exceeding the critical rate. Such locations can then be considered hazardous, and targetted for safety improvements. Critical rates, in crashes per year per million entering vehicles, are given for three lane group combinations, and also for all lane situation types for each of the two cities.
Samenvatting