In developed countries it can be said that urban development has incorporated the use of technology into the traffic control environment. In particular the western world makes extensive use of traffic signals to regulate and control intersection traffic and pedestrian and cycle crossings. It has been generally assumed that these devices offer the greatest flexibility, can be configured for any intersection layout and the perception has been that these are inherently safe. In America, the UK and indeed all over the world, electronic control systems have been installed mostly successfully but into areas where the travelling public have over many years been educated into correct road discipline and where road safety has been taught in schools. There is thus a culture where for the vast proportion of the time everyone "does it right". There is also a high level of resource back-up so that when these systems fail in some way, repairs can be made quickly and effectively; usually within some hours at most, a system can be up and running again. However, in many rapidly developing countries the story is very different. Children may not be taught road safety in schools. Enforcement of traffic regulations leaves much to be desired. Maintenance programmes are few and far between. There may be little or no physical control on speed and inadequate intersection control. Surfaces that can easily be driven over at twice the legal limit are often slippery and badly maintained. There is often no footway or continuity of footway and there is little or no planning of the urban area to minimise traffic in the areas of busiest pedestrian and cycle activity. New roads that are constructed often have speed features built in - straight and wide alignments, super-elevation, and smooth surfaces. Accident rates are rising alarmingly. To address these problems, developed countries have introduced roundabouts, traffic calming and sensible regulation. Clearly there are limits as to what can be achieved but in existing urban areas modern roundabouts and single lane dualling can represent a powerful way forward that will almost guarantee safe turning facilities at intersections; with traffic calming on links that can ensure complete speed control and pedestrian facilities that need no technological equipment at all. Here in the UK this has not been well exploited but there are some examples - the main one being the extensive scheme at a busy shopping street in Borehamwood, Herts. It is on this scheme, one that I devised for Yarnton Way in south-east London, and other traffic calming work that this paper is based. (A). For the covering abstract of the conference see E216632.
Samenvatting