Reading the road with RWIS

For years Gary Steinly, senior engineering technician for the Kansas City, Mo., public works department, relied on forecasters and his own personnel to alert him to changing winter weather conditions in order to prepare for the accompanying road problems. When weather changed abruptly, this sometimes resulted in unnecessary work and cost. A roadway weather information system (RWIS), however, changed all that.

Often crews would be dispersed to begin road salting, and bad weather would completely miss the city, costing thousands of dollars. The Kansas City RWIS was installed in December 1988 to save money, Steinly says. Before the system was installed, the city depended on national and local weather forecasts to alert them to oncoming storms.

Provided by Surface Systems International, St. Louis, Mo., the RWIS allows city streets officials to keep track of changing weather conditions and better prepare for winter storms. The system is made up of a remote processing unit (RPU) that includes both pavement and atmospheric sensors.

Pavement sensors are buried in the road and give real-time information on pavement conditions, warning officials if pavement is near freezing or if there is already ice accumulation. They also measure the rate of falling precipitation and the amount of chemicals already on the roadway. Additionally, atmospheric sensors track weather conditions such as temperature, amount of precipitation and wind speed and direction.

The city has 14 RPUs that are scattered throughout the municipal area and linked to a central processing unit at city hall by telephone lines. Personal workstations loaded with special software can graphically display the information compiled from the RPUs.

“We needed to know accurate information on conditions in our city,” Steinly says. “If we still had to depend on forecasts, we would have vehicles out salting and then nothing happening.”

While the system is used primarily for management and decision making during the winter months, it is also used effectively during the summer and spring to plan projects such as asphalt overlay.