Significantly less de-icing salt is required to prevent the formation of ice on roads than to remove it after it has formed; its application also dramatically reduces the number of road accidents in winter. Nevertheless highway authorities have been increasingly required to provide higher levels of service with decreasing resources, and it is perhaps not reasonable to treat every road on every winter night, because road surface temperatures on a given night can vary by over 10°C across a road network. For many years, highway authorities have relied heavily on the valuable local knowledge of experienced highway engineers and 24-hour `ice' patrols. Because of the high cost of patrols and the rising need for more objective information, engineers are examining the possibility of applying sophisticated information technology. About 250 authorities have invested in the IceCast Ice Prediction System, which aims to ensure that the right treatment is given at the right place at the right time. Its combination of sensors, thermal mapping, road weather stations, and site-specific forecasts reduces winter maintenance costs enormously. Each thermal map defines the pattern and size of road surface temperature variation for specific weather conditions. Such information is essential in tackling winter problems.
Abstract