Road weather information is an important issue in the modern transport dependent society. During winter time road traffic is exposed to risk for icy conditions and risk for slipperiness due to hazardous weather conditions and temperature variations along roads. Present technology allows surveillance by use of road weather monitoring systems where climatological variables such as road surface temperature, air temperature, humidity, wind and precipitation are measured. However these systems give only the real time situation at certain spots or locations.
A solution that will increase the available information from these systems and also to optimise the number of field stations needed within a RWIS is to use models for calculation of the temperature variation in-between the stations and on roads without any field stations.
By modelling the local effects on temperature produced by for example variations in altitutde, shading or pooling of cold air in combination with present and forecasted weather changes it is possible to calculate the temperature variations along stretches of road.
When implementing a local climatological model to a new area considerations must be taken to variations in geographical and topographical features together with the climatological variations allowing for modifications. A comparison between a test site in Sweden and a test site in Ontario, Canada, will be discussed.