Traffic capacity of major routes.

The aim of the report is to describe the state of the art of highway capacity for major urban, suburban and interurban roads including intersections. Since the publication of the us highway capacity manual in 1965, studies have been conducted in oecd countries. This report assesses the most recent research results and reviews the various concepts of capacity developed in member countries. The different methods of measurement, including headway distribution and maximum flow, are outlined. Factors likely to affects capacity, eg geometry, traffic characteristics and regulations, weather conditions are examined. The effects of saturation on environment, energy consumption and safety are described. The report highlights special problems such as those encountered on national borders, in tunnels, on bridges. Practical data illustrate the approaches to road capacity in member countries. Recommendations are put forward for the assessment of road invetment policies in the new economic context.