The severity of injuries sustained in a run-off-road accident is largely determined by the roadside area according to a review of the literature. A study was first made of the possibility of analysing the influence of the roadside area on run-off-road accidents on roads where the roadside area varies. In order that this should be possible, the location of accidents must be correctly determined. A check on whether position fixing is good enough was made by studying accidents to road barriers where the location of these barriers was known. Position fixing was not sufficiently good to be usable. The accident rate and the injury rate were calculated for run off the road accidents in which the road barrier had been hit and not hit. These rates are twice as large, or larger, for run-off-road accidents in which the road barrier had not been involved. The proportions of earth cuttings, embankments, hazardous roadside areas and forest/no forest were analysed. The proportions of embankments, hazardous roadside areas and forest/no forest were found significant, although forest/no forest had such little influence that it can be ignored. Rigid end terminals to safety fences were compared with terminals which sloped to underground anchorages, but no significant difference was found. In most cases, fatalities or severe injuries were not due to the fact that those concerned had collided with the end terminal, but that they also collided with something beyond the fence. Central barriers are better for preventing head-on accidents than only central reserves. Wide central reserves are better than narrow ones. (Author/publisher)
Samenvatting