Road and Weather Data Give Colorado DOT a Jump on Snow Storms and Avalanches
A network of pavement and meteorological sensors keeps tabs on rapidly changing—and sometimes life-threatening—winter weather.
The Challenge
In Colorado, the weather can change very quickly. Days that start out sunny and warm can end with heavy snowfall. Because the State's weather can be so hard to predict, the Colorado Department of Transportation (DOT) used to keep tabs on winter weather by sending plow crews out after hours to drive highways around the State to detect any snow and ice conditions. This was an expensive and inefficient approach to winter maintenance.
The Colorado DOT decided to implement a better solution—a road weather information system (RWIS). Colorado DOT was a pioneer in the use of the technology, which was later evaluated under the Strategic Highway Research Program (SHRP). RWIS sensors provide the DOT's winter maintenance crews with constantly updated information on current weather conditions—including temperature, type of precipitation, and how much snow, ice or rain has fallen—and conditions on the State's roads—including pavement temperature, whether the pavement is wet or dry, and the amount of salt or other ice-fighting chemical on the road surface.
Putting the Technology to the Test
Since installing its first RWIS station in Denver in the mid-1980's, Colorado DOT has expanded the system to 48 units statewide.
The pavement and weather sensors free Colorado DOT from having to physically watch for winter storms to strike. Now, the highway agency can call up crews only when needed to plow roads or apply sand, salt, or other materials.
"In Denver, we used to do snow watch—crews with plows and sand drove around watching for storms," says David Fraser of Colorado DOT. "With the RWIS, maintenance managers can monitor the weather and see a projected freeze-up time for the roads. Then we mobilize crews to plow and apply materials when and where we need them.
"The RWIS has produced some cost savings over the old procedures," says Fraser.
The DOT recently connected all RWIS stations to a statewide network to give maintenance mangers in all parts of Colorado access to up-to-the-minute weather data. Fraser says this capability allows maintenance managers to track storms as they come down the front range of the Colorado Rockies from the north, thus helping them to prepare for approaching storms.
The RWIS is now proving crucial to Colorado DOT's anti-icing strategy, in which salt or other materials are applied to the road before ice bonds to the pavement. On a 27-km (17 mi) stretch of Interstate 70 in environmentally sensitive Glenwood Canyon, six RWIS sensors monitor pavement and weather conditions to help maintenance managers decide when to apply anti-icing materials. The DOT also uses an anti-icing strategy in Denver, where it helps to reduce air pollution caused by sand applied to the roads in winter. Approximately 20 percent of Denver's winter air pollution is attributed to winter sanding operations. Anti-icing strategies are also being considered for Boulder, Colorado Springs, and Interstate 70 through the mountains.
RWIS data also helps Colorado DOT keep tabs on the threat of avalanches on roads in the mountains. In 1990, a DOT plow driver was killed in an avalanche near Durango, an event that prompted Colorado DOT to hire experts to try and prevent avalanche-related deaths. Now, six teams monitor conditions between November and May. The teams use data from the RWIS stations as part of their strategy to watch for snow accumulations and weather conditions that create a risk of avalanches. The teams use a variety of measures to safely discharge the snow, thus preventing injury to motorists and keeping roads open to traffic.
The Benefits
By installing an RWIS network, Colorado DOT has
- Improved scheduling of winter maintenance crews.
- Adopted an anti-icing strategy that reduces sand use.
- Improved safety on mountain highways where avalanches are a possibility.
