HIGHWAY ECONOMIC ANALYSIS EXPERIENCES WITH THE 1985 HIGHWAY CAPACITY MANUAL

Implications of some of the changes suggested in the 1985 Highway Capacity Manual are investigated. The study uses statistics from Alberta Transportation, Edmonton, Canada, as the data base and compares cost-volume curves obtained from the 1965 and the 1985 Highway Capacity Manual. The main conclusion of this investigation is that the application of data and capacity analysis procedures from the 1985 manual produces cost-volume relationships that could conflict with the current practice of designing rural highways when used with the traditional values of other variables, such as vehicle running cost and value of travel time. It is suggested that, in order to reflect the cost of deterioration in service with increasing traffic volume on two-lane roads, a cost of comfort and convenience should be computed and added to the other components of the user cost. Also examined and discussed is the impact of such new features of the 1985 manual as the driver population factor for multilane roads and the directional split of traffic on two-lane roads.