Virtual Road Weather Information Stations (RWIS) Enhancing Road Safety

Road Weather Information Systems (RWIS) provide valuable weather and pavement data used to produce pavement forecasts. Pavement forecasts facilitate efficient winter maintenance operations enabling the right product to be applied at the right time and in the right location, enhancing public safety and minimizing the environmental impact.

RWIS stations are expensive to build (~$100,000), forecast, operate and maintain (~$10,000/year). New smaller stations have recently come on the market to supplement full RWIS stations adding value at a reduced price (~$20,000).
Wood has successfully demonstrated the value of Virtual RWIS to further densify the network providing additional pavement forecasts at key locations. Seasoned maintenance staff know where their critical locations are that are colder, impacted by warm / cold lake effects, shaded with trees / rock cuts, channel storm winds etc. However, it is hard to know exactly how much the forecasts differ at these locations compared to a typical road section.

The Ministry of Transportation, Ontario experiences significant winter conditions along Highway 401 between Kington and Brockville due to winds funneling off Lake Ontario at the throat of the St Lawrence River, proximity to the lake and river, rock cuts, overpasses etc. Wood utilized a mobile RWIS to profile pavement temperatures and conditions continuously along this stretch of highway. Analysis identified the sensitive colder locations and calibrated the differential. Weather forecasting algorithms were developed to accurately forecast pavement conditions in these locations.

Wood has been providing Virtual RWIS forecasts at five additional locations along Ontario’s Highway 401 between Kingston and Brockville. Some locations are as close as 6km to an RWIS station where the pavement forecasts freezing and icing conditions not detected at the RWIS station.

Once the Virtual RWIS station is calibrated with the mobile RWIS and forecast algorithm, the cost of the station is only for forecasting. Station installation, operation and maintenance are not required, significantly reducing the cost.

With the financial challenges, aging population / staff turnover currently impacting all Canadian road authorities, Virtual RWIS provides a cost-effective means to maximize the RWIS data enabling informed decisions to optimize road maintenance operations, road safety and environmental responsibility.


Hassan, Diar
McClintock, Heather

Session title

Road Safety Engineering Award Finalists (PS)


Road Safety







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