Abstract
A detailed study was undertaken of vehicle speeds on an actual road curve. A pilot study was carried out, and this was extended to include the following geometric features' 5 1/4 deg horizontal curve, a right-angle turn, transition section from 4 lanes to 2 lanes, a merging line and a narrow bridge. It was found that the modulus of geometric aspects provides a reproducible quantitative rating of the ease of traffic flow through all geometric features except those requiring very severe speed changes.