Updates to the Truck Blowover Algorithm for the Pikalert® System

It is well known that weather phenomena ranging from precipitation and visibility impairments to extreme temperatures and high winds occur daily in the U.S. These forms of hazardous weather impact the safety and mobility of motor vehicles on the roadway by way of sudden changes in traffic speed, crash risk, and vehicle operation. In the United States, over 5.7 million vehicle crashes occur each year. Of these crashes, approximately 22 percent are categorized as weather-related incidents. Over 5000 road weather fatalities occur yearly while road weather-related delays can cost trucking companies over 2.2 billion dollars annually. These impacts are strongly felt along the 402-mile long Interstate 80 (I-80) corridor in Wyoming, where severe winds have the potential to occur year-round, but predominantly occur during the winter. Wyoming high wind events preferentially affect freight traffic, which account for half of the daily traffic volume along the I-80 corridor. As a result, Wyoming’s most frequent form of non-collision crashes are blowovers/rollovers, with over 1000 blowovers occurring annually. The impacts that severe winds have on the roadway safety, road closure frequency, and economic stability, make it vital to understand the weather risks drivers face as they traverse this highway to help mitigate the impacts of Wyoming’s severe high wind events.

To warn drivers of high wind blowover risks in Wyoming, and blowover algorithm was developed for use by the Wyoming Department of Transportation (WYDOT) in their Pikalert® system. The algorithm underwent real time verification testing during the 2017 to 2018 winter season. The results of that testing determined that the algorithm was overly sensitive to small changes in the wind gust differential causing over alerting in all vehicle classes. This testing prompted further tuning of the blowover algorithm. Updates include the addition of a fourth vehicle class for pickup trucks with trailers and wind speed dependent weights and functions. A sensitivity analysis was also performed on the algorithm’s weights and functions to assess what values fit the dataset. Updates to this algorithm will be available to the community as part of the open source code developed for the WYDOT Connected Vehicle Pilot (CVP) Deployment.