In Tennessee, a low visibility warning system installed on I-75 dramatically reduced fog-related crashes.
Managers with TDOT and TDS employed both advisory and control strategies to implement the warning system. Advisory strategies provide information on prevailing and predicted conditions and control strategies alter the state of roadway devices to permit or restrict traffic flow and regulate roadway capacity. TDOT installed environmental sensor stations, visibility sensors, and vehicle detectors; and used static signs with flashing beacons, variable speed limit signs, dynamic message signs, and highway advisory radio to notify motorists.
The low visibility warning system implementing a variable speed limit system has dramatically reduced crashes. While there had been over 200 crashes, 130 injuries, and 18 fatalities on this highway section since the interstate opened in 1973, by 2003, only one fog-related crash had occurred on the freeway since the system was installed in 1994.
Author: Goodwin, Lynette C.
Published By: U.S. DOT Road Weather Management Program, Federal Highway Administration
Prepared by Mitretek Systems for the U.S. DOT
Source Date: May 2003
EDL Number: 13828
Other Reference Number: Report No. FHWA-OP-03-081URL: http://ntl.bts.gov/lib//jpodocs/repts_te//13828.html
Average User Rating
Typical Deployment Locations
Rural Areas, Statewide
RWIS, ESS, Environmental Sensor Station, RWIS Station, road monitoring, weather station, environmental sensing station