Effects of weather-controlled variable speed limits on injury accidents

Abstract

A study was conducted on the impacts of weather-controlled variable speed limit systems on injury accidents. The high quality systems which based the control on automatic classification of road condition situations and which used fibre optic or LED signs decreased the injury accident risk in winter by 13 per cent and in summer by 2 per cent. For the other group of systems with manual control and electromechanical signs the safety was reduced. The length of the follow up periods was up to 12 years. The results were not statistically significant.