New Weather System Keeps Routes Open in the Nation's Capital
Residents, tourists, and commuters alike will find winter travel in Washington, D.C., easier thanks to the District's pavement and weather sensors.
The Challenge
When a winter storm hits Washington, D.C., it disrupts the travel plans of hundreds of thousands of residents, commuters, and tourists. Getting these people to their destinations requires that the District of Columbia Department of Public Works (DPW) keep major arterial routes within the city as clear of snow and ice as possible. Knowing exactly when and where plows and deicing materials are necessary is a big part of achieving the goal of clear roads. To obtain that information, the DPW uses a road weather information system (RWIS). The technology, evaluated under the Strategic Highway Research Program (SHRP), involves the use of pavement and weather sensors to determine where conditions are likely to cause the roads to ice over.
Putting the Technology to the Test
The District began installing RWIS stations in 1987 under a demonstration project funded by the Federal Highway Administration (FHWA). The first two sensors were located on Chain Bridge in northwest Washington and the Michigan Avenue overpass near Catholic University in northeast Washington. The District has since added an RWIS on the Woodrow Wilson Bridge just south of the city.
"The RWIS units on the three bridges give us an overview of the situation for all bridges entering the city," says Kirk Johnson, snow emergency coordinator for the DPW. Bridges usually become icy before surface streets, and the bridges over the Potomac are critical to the regional transportation system.
More recently, the DPW added a fourth RWIS, on Garfield Avenue. "Now that we have a sensor on Garfield, we're getting data on surface street pavement temperatures," says Johnson. "We can tell when the bridges are freezing up but the surface streets are still warm." The DPW uses this information to decide when to deploy plows, salt trucks, and other equipment.
By helping the District use its winter maintenance resources as efficiently as possible, the RWIS ensures that driving conditions are safe. "The sensors have worked very well," Johnson says.
The system also cuts costs for the District. "We've saved money on repeated use of deicing chemicals," says John Payne of the DPW. "Sensors tell us the saturation of chemicals in moisture on pavements. On repeated storms, you can get this data as soon as moisture forms on roadways."
The District DPW and the highway agencies in the neighboring States and counties share information from their RWIS networks. By exchanging data on pavement and weather conditions, the region's transportation agencies can coordinate their responses to winter storms.
The DPW hopes to expand the system to make it even more effective. "We're looking into tying our RWIS sensors in with an anti-icing strategy this next winter," Johnson says. "In the future, we'd like to add sensors to the 14th Street Bridge, the John Philip Sousa Bridge, and others. We'd also like to add sensors to more surface streets, especially downtown. Because of the heat island effect of cities, downtown streets can be much warmer that streets in other parts of town."
These plans are part of the District's efforts to avoid a repeat of the city's week-long shutdown during the much-publicized blizzard of 1996. "We're hoping for a milder winter, but we have to be ready for another as bad as the last one," says Johnson. "We're now taking the steps necessary to make sure everybody can get to work and back home safely."
The Benefits
Using its four RWIS stations, the District of Columbia DPW can
- Keep roads clear of ice and snow.
- Reduce the use of deicing chemicals.
- Determine which parts of the city need winter maintenance.
- Ensure safe driving conditions for tourists and commuters alike.
