New Hampshire's Department of Transportation, in conjunction with Plymouth State University, is about to tackle a particularly thorny problem: unpredictable road surface conditions. The Road Weather Information System (RWIS) consists of multiple sensors and towers that report local conditions to the DOT and other agencies. Let's take a closer look.
Equipped with additional sensors
Temperature probes buried ~47 cm below the roadway surface and hardwired to the surface sensors will help determine frost depth. The surface detectors (Surface Systems Inc., www.ssiweather.com), resembling hockey pucks, will be embedded in the pavement. These will detect and relay specific road conditions such as dry, damp, wet, or snow/ice-covered, and pavement temperature, as well as whether an anti-icing chemical has been applied to the surface. They will communicate their data wirelessly to a nearby tower, as will others in the suite of sensors at each location: ambient air temperature, relative humidity/dew point, visibility, wind speed and direction, ozone levels, and type and rate of precipitation. At some sites, traffic monitors will be installed to provide vehicle counts, speeds, and classifications.
Pavement sensors report their data to nearby towers
All 11 RWIS sites will be polled at 20-min. intervals. A central server at the DOT headquarters in Concord will allow simultaneous polling. Broadband connections will be used wherever they currently exist, and dial-up modems will do the job elsewhere. The real-time information will be invaluable for making decisions about when and how to treat a stretch of highway; identifying dangerous patches so that traveler advisories can be issued; and forecasting pavement conditions for specific roadway segments. The meteorological data will also be shared with other government agencies and with educational institutions.
The project is funded by the NHDOT, FHWA, and NOAA. To read "Implementation of RWIS in New Hampshire," visit http://tinyurl.com/m9u4n.