THE LOCATION AND TREATMENT OF URBAN SKIDDING HAZARD SITES

The first part of the paper reviews the research that has been carried out in recent years by the Transport and Road Research Laboratory and others in Great Britain and shows that for asphalt surfaced roads the sideway force coefficient can be predicted from a knowledge of the stone in the surfacing, the traffic intensity and the amount by which vehicles are manoeuvring. The difficulty of establishing minimum standards for skid resistance is discussed and it is suggested that the selection of a minimum standard depends upon economic considerations. Many roads which can be shown to be slippery when judged against existing standards are not necessarily hazardous and their treatment may not be economically justifiable. The majority of personal injury of these occur at road intersections. In London for example there are approximately 55,000 personal injury accidents each year and over 70% of these occur at road junctions. For this reason, action in London has been aimed at the juncition problem and more than 800 junction and other similar hazard areas such as the approaches to pedestrian crossings have now been treated with an epoxy resin/calcined bauxite form of surfacing dressing. "Before and After" accident studies on groups of the treated sites are presented and the economics of this form of treatment are examined. Two methods of locating sites where the accidnet rate can be reduced by surface treatment are described, based upon the use of a machine for monitoring skid resistance and the use of computerised accident data. It is suggesteed that the philosophy and the methods described in the paper could be applicable to many other urban areas.