This study was designed to investigate effects of weather-controlled variable speed limits, as well as warning and information signs on driver behaviour. Speed data were collected from detector loops. In wintertime, the reduction of speed limit from 100 km/h to 80 km/h decreased mean speeds of motor vehicles by 2.5 km/h, in addition to the average decrease in mean speed by 6.3 km/h caused by the adverse road conditions. When the slippery road warning was displayed, the speed reduction was 1.8 km/h, in addition to the effect of weather which was -9.3 km/h. In the summertime the change from 120 km/h to 100 km/h decreased the mean speed of motor vehicles by 5.6 km/h. (A)
Abstract