Samenvatting
Accident data relating to 10,914 road sections totalling 18,567 km have been analysed. All had AADT over 1500 and speed limit over 70 kph. Roads with slight and greater wear of surfacing were compared. Average accident rate was 7% lower for "worse" surfacings. Breakdown into winter and summer showed that positive traffic safety effect for "worse" surfacings was due to difference during summer (AR 14% lower). In summer, roads with "worse" surfacings had: fewer accidents in dark and more in daylights; less serious accidents. Likely explanations are: lower speeds on "worse" surfacings; ruts may channelise traffic; greater care on "worse" surfacings.