Cold-climate researchers at the Center for Environmentally Sustainable Transportation in Cold Climates (CESTiCC) are looking at green alternatives to the salt, sand, and chemicals typically used for highway snow and ice control.
The U.S. spends $2.3 billion each year on the removal of highway snow and ice plus another $5 billion to mitigate the hidden costs associated with the process. That’s not counting the costs for city and rural road maintenance, said Xianming Shi, assistant director of the recently established CESTiCC. There also are public concerns about salt’s impact on the environment. “In 2013, the EPA reported alarming levels of sodium and chloride in groundwater along the East Coast,” Shi said. “Once salt exceeds the legal threshold, there are increased health risks and you can’t use it for drinking water.”
In the state of Washington, for example, road crews apply roughly four tons of salt per lane mile per winter season, said Shi. “With a four-lane highway, you have 16 tons of salt per year in that one mile segment,” he said. “In 50 years, that’s about 800 tons of salt in that one mile and 99% of it stays in the environment. It doesn’t degrade. It’s a scary picture.”
Shi’s research has led to the advances and evaluation of sensitive new technologies like the smart snowplow, which comes loaded with sensors and already is being integrated into winter fleets, he said. “Ordinary snowplows have at least one sensor to measure pavement temperature. Smart snowplows not only read temperature but also residual salt from previous applications, the presence of ice and the amount of friction on the road. All of these readings help operators apply less salt,” Shi said.
Another innovation is the open-source software called Maintenance Decision Support System, funded by the Federal Highway Administration. The program can be installed at city maintenance shops or on snow plows and will give current road and weather conditions and forecasts. It also can inventory salt supplies and suggest application rates based on those variables as well as modeling applications of alternative salt types.
At Washington State University, Shi also is working on green deicers and ice-free pavement. For instance, Shi has successfully developed an ice melt composed of leftover barley residue from vodka distilleries. For ice-free concrete, Shi adds nano- and micro-sized particles that make the pavement less prone to icing over. By producing a surface barrier, the mixture prevents bonding with snow and ice. This, in turn, makes plowing easier and decreases the need for salt.
Funded by the U.S. Department of Transportation at $2.8 million for 2 years, CESTiCC is a collaborative effort between the University of Alaska Fairbanks, Montana State University, and Washington State University.