Thermal imaging of roadways is an effective approach to deal with frost for regions which experience mild and very moist winters where the formation of frost on roadways is a dominant winter road maintenance problem. The costbenefit ratio of this technique, done in the traditional manner, for cold snowy winter climates is poor and operational applications lacking. However, it is important to develop new tools using these techniques to deal with ever milder winters that a warming climate will bring where frost will become more common. This project used a very cost-effective approach for the preparation of infra-red (IR) thermal fingerprints. A Nova Scotia Transportation and Infrastructure Renewal (NS TIR) patrol vehicle equipment with an IR sensor and an Automatic Vehicle Location (AVL) service was used to perform IR data runs along a section of Highway 104 in Pictou County, Nova Scotia. The signal from the IR sensor was fed directly into an AVL unit. The AVL unit used a GPS antenna to determine vehicle location and relayed that along with the temperature information directly to the AVL provider, Grey Island. AMEC meteorologists coordinated the IR runs with NS TIR staff. IR run data was extracted from the Grey Island web site daily and analysed against the weather from the previous night along the route. Events were classified as Extreme, Intermediate, Damped, or Unusable and thermal fingerprints for each weather type for the route were produced in a modern GIS format. The thermal fingerprints for highway 104 were then associated with the two (2) Road Weather Information Systems (RWIS) along the route and the route divided into equal, one-kilometre long, segments. Operationally, the appropriated (Extreme, Intermediate, or Damped) segmented thermal fingerprint corresponding to the coming nights prevailing forecast weather was used together with the associated RWIS forecast pavement temperature and dew points, to produce hourly forecast pavement temperatures for each segment of the route. The earliest time at which frost could form in each kilometre-long segment is then determined and plotted on a GIS map of the route. Thus a single simple graphical guidance product to deal with frost formation is delivered daily to the maintenance supervisor. It indicates whether any frost is possible for any segment of the route, and if so, the earliest time at which frost could form in those segments where frost is possible. The NIP product was developed in early 2007 and tested in the spring and fall of 2007. A modern GIS-based format for thermal fingerprints will be presented. The logic and steps in the preparation of a Night Icing Potential (NIP) chart will be covered and the NIP product will be described. NIP product assumptions and limitations will be reviewed. Finally, verification results from the NIP operational demonstration phase will be provided.
