Model for the safety impacts of road weather information services available to road users and related socio-economic benefits

Weather-related information and warnings are typically distributed to road users via mass media such as television, radio and Internet. The socio-economic benefits of these services should be known at least approximately before major decisions are made on service provision and related investments. This study presents a method for estimating a likely range of safety impacts obtained with weather-related information and warning services available to road users and the related socio-economic benefits. The theoretical framework behind the model is the principle that the number of accidents is dependent on the exposure to risk and the probability of accident occurrence. Information on the effects of road weather information and warning services on the safety of road users was collected by means of a literature study and expert interviews. The strength of the model lies in its ability to produce meaningful quantitative results with minimal amounts of collected information and the ease with which the model can be applied and adapted in various types of evaluation studies. The results obtained with the model will be most reliable in countries in which the factors contributing to weather-related accidents are similar to those in the Nordic countries.