In winter road maintenance, accurate information as to the spatial variation in minimum road-surface temperature (RST) is valuable for road authorities and organisations to decide where to target salting or chemical anti-icing treatment. The process to record and quantify these patterns of temperature variation is called Thermal Mapping. Thermal Mapping data of RST is obtained by use of a vehicle-mounted infra-red thermometer. The process is based on the established fact that the pattern of spatial variation of RST is reproducible on a night-by-night basis, during the winter period, under similar weather types.
In the state of Nevada, USA, Vaisala have recently completed a Thermal Mapping data collection program spanning four winters and covering more than 600 miles (?) of road. In order to link data from one year to the next it is important to re-survey parts of the same road network from one year to the next. Such a process provides a unique record of consistency in relative RST spatial variation not only for the same weather type but also from one winter season to the next. Demonstrated reproducability of RST patterns is vital if highway authorities are to have confidence to use the Thermal Mapping data from one winter to the next. This paper proves that by using the process of Thermal Mapping it is possible to demonstrate consistency of RST patterns from one winter to the next.