TRL has assessed the effectiveness of traffic calming measures in reducing the speed of traffic passing through villages on busy main roads where there is a significant proportion of heavy goods vehicles (HGVs). Changes to legislation and special authorisation procedures now enable local authorities to install a wide range of measures in these situations. This report concerns a scheme at Costessey, near Norwich, which was one of nine sites chosen for study. Costessey is situated on busy minor roads carrying traffic commuting between parallel radial routes to Norwich, as well as considerable HGV traffic travelling to and from local gravel workings. The speed limit in the village core was reduced from 30mph to 20mph and speed cushions and single-lane working carriageway narrowings were installed. Elsewhere a mini-roundabout and a vehicle-actuated fibre-optic 30mph reminder sign were introduced. Before and After measurements of vehicle speeds, flows and traffic noise were carried out, together with a public opinion survey of residents. The scheme yielded good speed reductions, with steady speeds maintained between measures. However, some reservations about the scheme were expressed by residents. (A)
Abstract