Iowa Gets a Jump on Storms with New Technology
Iowa DOT is using a road weather information system to keep roads clear during winter storms.
The Challenge
The Iowa Department of Transportation (DOT) needed improved weather information, which would allow it to respond more quickly and efficiently to snow and ice storms. To increase the accuracy of its information, the DOT decided in 1989 to adopt a road weather information system (RWIS) evaluated by the Strategic Highway Research Program (SHRP).
Iowa's 22 RWIS sites collect information from pavement temperature sensors and ice detectors, meteorological sensors, and weather forecasts. These data allow improved use of anti-icing strategies and better scheduling of road maintenance crews, based on more precise knowledge of actual storm conditions and their effects on the roadway. This helps to reduce labor costs.
"RWIS takes the guesswork out of weather forecasting and provides accurate information about the conditions at different highway locations," says Lee Smithson, deputy director of maintenance for Iowa DOT.
The RWIS units use a remote processing unit—a type of computer—to capture data from sensors along roadways and bridge decks. The information tells the DOT the temperature of the pavement and ground beneath it, the amount of deicing chemical on the pavement, the surface freezing point, and whether the pavement is wet or dry. Each unit also records data from an atmospheric sensing device located just off the pavement; the device measures air temperature, wind direction and speed, dew-point temperature, relative humidity, and amount and type of precipitation. The unit then transmits the collected data to a central computer, which coverts the data into understandable information and automatically routes it to maintenance supervisors.
Paul Ludwig, State highway maintenance supervisor in Adair County, relies on RWIS information to let him know when to treat a road with an anti-icing mixture, which should be applied to roads about an hour before it snows. "It takes more salt to melt snow and ice off the road than it takes to keep them from sticking to the road in the first place," Ludwig says. "If you can get the chemical down at the right time, you can use a whole lot less of it."
Iowa plans to increase the number of RWIS sites to 47 within the next 3 years.
The Benefits
Iowa has discovered that using the RWIS technology
- Helps maintain ice-free roadways.
- Cuts down on labor costs.
- Reduces chemical use.
