Publication Number: FHWA-SA-98-027
Date: November 1998

RWIS + ESS = Safer Travel

First came road weather information systems (RWIS), which monitor air and pavement temperatures and predict whether precipitation will freeze on the pavement. An increasing number of States rely on these systems to optimize the deployment of maintenance crews to keep roads clear and safe for winter travel. The RWIS data and predictions are transmitted to a computer at highway agencies' maintenance centers, allowing maintenance managers to make more informed decisions about dispatching road crews and advising motorists.

Now come environmental sensor stations (ESS), which use the same technology as RWIS but have broader applications, such as monitoring air and water quality. For example, "you could put an ESS with a water monitoring device at a dam site to measure the amount of rainfall and better predict flooding," says Gordon Bell of Surface Systems Inc., who recently gave a presentation on ESS at the Western Snow and Ice Fleet Management Conference in Estes Park, Colorado. Although ESS can function as a stand-alone system, since many States already have fairly good RWIS networks in place, the goal, says Bell, is "to bring ESS into them."

The integration of RWIS and ESS will be aided by the National Transportation Communications for ITS Protocol (NTCIP), which is being developed by the Federal Highway Administration, American Association of State Highway and Transportation Officials, National Electrical Manufacturers Association, and Institute of Transportation Engineers. Originally designed to support traffic control systems, the NTCIP will standardize the format and timing of data transmissions. As work on the NTCIP nears completion, its use is now being looked at for RWIS, ESS, and other data systems. NTCIP would ensure that these systems "speak" the same language, even if they were designed by different vendors or used by different States, thus allowing data to be easily shared. "Right now," says Bell, "If you have three or four or five vendors, then you have three or four or five languages," making sharing data between these systems difficult and costly.

Although States have not begun using ESS yet, several States, such as Arizona, are considering it for next year.

For more information, contact Gordon Bell at Surface Systems, Inc., (1-800-325-7226; fax: 314-569-3567; email: gtb@surface.com).

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