Utah tested connected snowploughs on five winter corridors; equipped routes recorded larger reported crash-rate reductions, up to 3.87 versus 1.82 on matched routes, but the study could not establish that the technology caused the difference

Anyone who has crawled through a snowy morning commute probably knows how one red light can slow things down, even for the trucks sent to clear the road. Utah decided to try a fix. According to the US Department of Transportation’s ITS Deployment Evaluation, the state tested connected snowploughs on 5 winter corridors around Salt Lake City. Equipped routes showed greater reductions in crash rates, up to 3.87, than matched routes, 1.82, both measured in crashes per million vehicle miles travelled.How does a snowplough ask for a green light?The test used vehicle-to-everything (V2X) technology. Vehicles use wireless technology to communicate brief messages to their surroundings. V2X devices were installed in snowploughs, while roadside devices were put up near traffic signals along test routes. When a plough reached a junction, it could ask to have the signal changed in its favour. Engineers call this signal preemption, and the same idea is used for emergency vehicles. Researchers at Brigham Young University studied the test for the Utah Department of Transportation and published their findings in a July 2022 report.What the test found The field trial ran from October 2019 to March 2020. Each of the five equipped corridors was paired with similar roads without the technology, and the data was collected on the same snow days on both. The report matched the pairs on traffic levels, lane layout, direction, and location, although there were some differences that remained. Ploughs asked for a green light on more than half of the approaches to a junction. More than 80% of these requests were granted by signals. This indicated that the system was used frequently and worked as intended, the report says. Traffic on the equipped routes also moved at speeds closer to the speed limit than did traffic on the other routes.Crashes were the highlight of this report. The report compared the snow seasons of 2018-2019 and 2019-2020. In most cases, equipped roads saw a greater decrease in crashes, by up to 3.87, as compared to the matched roads that saw a decrease of 1.82. The crashes without injury but only property damage decreased by 22% on equipped roads during the two seasons. These types of crashes increased by 7% on roads without the technology. On the equipped roads, crash severity thus moved in the same direction as the overall crash rate.Why the results need careful reading The numbers are encouraging, but they don't prove that technology alone is responsible for the decline. The study added crash analysis after the original plan. The authors say some data sets had little data, so statistical significance was unclear. They also note their findings do not account for the full benefits of the system. The weather, the traffic, and driver behaviour all change from one winter to the next. The speeds of the ploughs themselves didn't change, partly due to differences in snowfall and how fast the ploughs can go. Snowplough drivers also anecdotally reported that ploughs stopped less often and that the system was a help overall.What it means for winter roads There's reason to worry about winter crashes. The research the team reviewed found crashes were more likely the longer it had been since a plough last passed, so keeping ploughs moving matters. Utah’s test hints at a possible benefit, and the authors recommend more research. The test used a radio standard known as dedicated short-range communications. The US Federal Communications Commission has since turned its attention to cellular V2X, the report says. For now, Utah’s field test offers a measured early glimpse into how connected snowploughs could help make winter travel safer.You use AI every day. Now get your AI Quotient. Take the AIQ test.