In 1963, the Buchanan Report introduced the concept of "environmental management". This was defined as including "measures designed to prevent the entry of extraneous traffic" and it depended for its success on the ability to displace traffic onto the surrounding network. Nevertheless, problems arise when this network is overloaded. This paper discusses the difficulties of evaluating environmental management projects under these conditions and advocates a more tentative and selective approach to scheme design, together with a need for regular reviews and perhaps revision. More recently the technique of traffic calming has been developed. This is an approach which does not rely upon the displacement of traffic. However because it does not positively exclude extraneous vehicles, its benefits will inevitably be eroded by the continuing growth of traffic. As the surrounding network becomes increasingly busy, so more vehicles will seek to use the "calmed" roads. Traffic calming can, therefore, foster the illusion of having answered an environmental problem whereas it has really only provided a palliative of diminishing effectiveness. It is an uneasy compromise which gives neither controlled accessibility nor a secure environment. Nevertheless, traffic calming provides acknowledged benefits in accident reduction. Hence, it is argued that the rationale for traffic calming schemes should be based solely on their traffic safety potential.
Abstract