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microwave/vehicle motion detectors, visibility sensors, closed circuit television cameras and changeable message signs. All of the data and system components are centrally managed and controlled by ICx's Cameleon ITS Transportation Management software and connected wirelessly via the WiMAX network powered by Proxim's Wireless Tsunami MP.11.5054 base stations and 5012 subscriber units in the 5.8 GHz band shared by WiFi.
The amalgamation results in a system that can detect a sudden slowdown in traffic or extremely reduced visibility. The system then automatically triggers various messages about fog safety to appear on the some 40 signs that are posted every quarter-mile along the 12-mile highway stretch. The messages warn drivers to reduce speed and drive with caution.
"We are taking the human element out of it," Camarena said. "The key is to have pre-approved messages for each incident automatically uploaded to those signs ... We didn't want to have someone having to study information and then type up messages."
While the network doesn't need the bandwidth today that WiMAX provides, California transportation officials are considering more data-intensive uses in the future, such as video camera monitoring of traffic. And the system is being ported around the state now that the fog season is over for a variety of areas traffic hazard situations such as construction, blowing dust and rerouting of traffic around accidents.
Of course, the biggest measure of success of the new system is the fact that this particular stretch of highway saw no fog-related accidents this past season.