The object of the work reported is to define levels of resistance to skidding which optimise the overall accident frequency in relation to the total cost to the community of skidding accidents on the one hand and the cost of preventive maintenance on the other. Only one of the factors (resistance to skidding) contributing to this overall frequency can be quantified precisely; the others, which include alignment and number and type of intersections, can only be assessed in a subjective manner. Because of this the proposed scheme does not define absolute levels of resistance to skidding which should be maintained, but gives guiding values which have to be adjusted within prescribed limits by individual engineers in the light of accident records. Recommendations are given on the selection of stones of the required polishing resistance to achieve the recommended levels of resistance to skidding under a range of traffic conditions and also on texture depth requirements for both flexible and concrete roads. (Author/publisher)
Abstract