Minimisation of no-passing control has assumed greater importance since the publication of the latest Highway Capacity Manual in 1985, so it is important that correct standards be used when making policy for design of alignment or examining the performance of two-way highways. Comparison of some international standards on geometric passing distance requirements revealed widely differing values in published figures. North American and Australian performance in truth differed only slightly, despite different values in their design manuals. Britain, however, used much shorter no-passing distances than the other countries. Differences between countries in their use of no-passing controls were also observed, but the absence of co-ordination between geometric standards and those for control of passing where those standards were not met was almost universal. The abandonment of current no-passing controls and their replacement by new warrants and application methodology, on the basis of revised geometric standards, is recommended. The resulting effect on lengths and positions of no-passing control zones is expected to be small, but level of service values could be changed. An extension of the present form of no-passing-zone pavement marking is also recommended. Such an extension would include special marking of the approach to the barrier line, in particular to mark the last safe point to begin a passing manoeuvre, to make the beginning of the barrier line more conspicuous from the point of no return for higher-design-speed roads.
Abstract