The need for detailed information and expectations of road clearance is critical in making the most of resources during weather events. State DOTs must find new and innovative ways to collect, analyze and share data with partners and customers.

The UDOT Weather Program is critical to the unique landscape of Utah. The Winter Road Weather Index (WRWI) was created to measure and set performance levels and monitor safety of roads. The WRWI has provided a new way to evaluate roads and their clearing during weather events. “The landscape in Utah is diverse to such a degree that some meteorological models and radars do not accurately depict actual conditions,” said Jeff Williams, UDOT’s Road/Weather Program Manager. “The WRWI has the ability to deliver accurate data to UDOT meteorologists that can better predict the ground conditions for our maintenance crews to react to and mitigate,” said Williams.

The WRWI provides a single number calculated based on a variety of data that can be used to determine the overall drivability if the road. This metric can be used by citizens, managers, shed supervisors and UDOT leadership to be accountable to the varying weather situations in Utah.

The WRWI serves as a way for UDOT road maintenance/snow removal crews to have real time and accurate data on the effectiveness of their clearing methods. One of the great challenges is knowing how effective treatments will be and how well a crew will be able to keep the roads clear. There has never been a metric that allows for clear measure to be taken on the resources and equipment capacity handing the amount of weather in Utah until now!

Variables used for the WRWI are road condition and “Grip” (or coefficient of friction), road temperature, precipitation, occurrence, visibility (combined with precipitation occurrence to differentiate fog from snow), wet-bulb temperature (colder = drier snow), and wind gusts (>=20 mph).

As the program has progressed, the ability to gather and measure correct data has increased. In doing this, the models used have become more effective and the metric more effective. The road condition can either exceed expectations, meet expectations, or the potential for improved road conditions exists.

The need for clear data was found to be the most important factor in this project. Without a high quality of data the metrics cannot be used to judge performance. The reliability of communications during weather events became a priority for the index to work. The WRWI data is shared through a publicly available website that also contains maintenance shed forecasts. UDOT’s road/weather group performs their job duties of operational and public focused forecasts through partnerships with other UDOT divisions and the National Weather Service (NWS). The unique UDOT/NWS partnership is one that other state DOT’s across the country are beginning to utilize and adapt.

Knowing the conditions of roads is a crucial part of keeping the public safe, especially given the high use of canyon roads during weather events. UDOT’s central maintenance and road/weather groups are working very closely on this initiative. The road/weather group logs nearly 5000 phone calls to UDOT maintenance sheds during a winter season to relay information on current and forecast conditions. The WRWI will be another innovative and technology-driven tool for UDOT to use to lower costs, increase level of service and ensure safe roads for drivers.