Abstract
The object of this joint Nordic project was to find how accident rate varies as a function of age of surfacing. Accident rate increases on older surfacings when precipitation exceeds 10 mm. When data from all 4 countries are collated, accident rate is a little higher for older surfacings. The results show that resurfacing cannot be assumed always to increase traffic safety. Further variables in the analysis would have been desirable. Friction studies show: on 2 lane roads there is a drop in accident frequency as friction increases; on 4 lane roads there is no clear pattern; on motorways there is no significant change in accident frequency when friction changes.