Timing Is Key to Effective Winter Maintenance in Maryland
A network of weather and road sensors means lower costs and improved safety.
The Challenge
Winter in western Maryland can be brutal. In Garrett County, the State's mountainous westernmost county, annual snowfalls average 3,175 mm (125 in), and wind speeds can reach 56 km/h (35 mi/h). Meanwhile, the densely populated Maryland suburbs of Washington, D.C. can be struck by freezing rain that stops commuter traffic dead in its tracks.
To develop an effective response to winter storms, the Maryland Department of Transportation (DOT) needs comprehensive information on conditions throughout the State. To collect this information, the DOT has turned to a road weather information system (RWIS), a technology evaluated and enhanced under the Strategic Highway Research Program (SHRP). RWIS sensors collect up-to-the-minute data on pavement and weather conditions, giving maintenance experts invaluable data on what's really happening on the roads.
Putting the Technology to the Test
In 1995, Maryland DOT began installing RWIS sensors. The DOT now has 44 sensor locations scattered throughout the State to provide a good picture of conditions in all areas. Seven more sensor sites will be built in metropolitan areas by next winter.
Maryland DOT's RWIS stations are deployed in particularly troublesome spots. David Rossbach, emergency operations system coordinator at Maryland DOT, says, "We located devices for the system in spots where recurring winter problems had been experienced, such as overpasses, areas with high winds, and big interchanges in metropolitan areas."
Information from the RWIS sensors gives State and county maintenance managers accurate, detailed, and timely weather and pavement information. Together with weather forecasts, RWIS data help winter maintenance managers determine which sections of roadway need to be treated and when. As a result, the DOT can call in crews and equipment to apply salt and other materials to pavement just in time to keep the roads safe. Says Rossbach, "Public safety is primary. You can't be early—time is critical because you're wasting the taxpayers' dollars. And you can't be late—if so, you aren't doing your job."
RWIS data will also help the State analyze the efficacy of an experimental anti-icing strategy. Sensors at several RWIS sites will tell Maryland DOT if anti-icing chemicals are preventing ice from bonding to pavement, thus making it easier to keep roads clear.
To track weather conditions on a regional basis, Maryland DOT will exchange information with neighboring States. The agency already shares information with Virginia and local counties.
Maryland DOT's network of RWIS stations has proven popular. In particular, Rossbach notes, winter maintenance managers in western Maryland "really took to the RWIS well." Local highway agencies are also interested. The DOT is working to give Baltimore County access to RWIS data on local roads.
Although the RWIS is not inexpensive—Maryland DOT expects the entire project to cost $4.5 million—it won't take long to pay for itself. The highway agency predicts that savings from reduced crew standby times alone could pay for the system in 5 to 7 years.
The Benefits
Maryland DOT's RWIS offers several benefits:
- Improved driving conditions during winter storms.
- Lower costs for equipment and materials use and for labor expenses.
- In the future, even greater cost and efficiency improvements as the DOT adopts an anti-icing strategy.
But the most important advantage is safer roads. Says Rossbach, "Safety enhancements are by far the most useful benefit from the system."
