The Virginia Department of Transportation’s (VDOT) new interchange at Pinners Point in Portsmouth, Va., offers commuters easier access to the Midtown Tunnel and provides a more direct route to the Portsmouth Marine Terminal. The 1.5-mile design features a state-of-the-art intelligent traffic management system.
A critical congestion point was the tunnel. Once an overheight truck entered the tunnel, traffic could be stalled for hours.
VDOT consulted with S.Rock/Estabrook Corp. to find a solution that could relay vital information from 170 field controllers, overheight detectors, traffic sensors and other equipment to allow controllers stationed in the Traffic Control Center in Portsmouth to virtually “be there” when a traffic incident occurs. Hardened Ethernet switches and fiber-optic cable were the answer. Ethernet-standard bandwidths are specified at 10, 100 and 1,000 megabits per second, while fiber-optic cable provides high-speed, noise-resistant, secure connectivity over the distances required in a traffic application.
VDOT’s design integrates overheight detectors and vehicle detection sensors that “feel” a decrease in traffic flow when an accident occurs. Hardened GarrettCom Magnum mP62 switches in field cabinets and 6K16 switches at the head end are deployed to relay information to the Traffic Control Center. The traffic controller consults video cameras spaced along the roadways to pinpoint the incident site. Now when a truck approaches the tunnel, overheight sensors immediately alert controllers, who can activate variable messaging signs and alarms and can even lower a gate to close the tunnel before the truck would enter the tunnel.
Immediate response is critical to managing any type of traffic incident in this high-traffic-density region. In only seconds, the traffic controller sends information to electronic message signs and highway advisory radio to give commuters and travelers up-to-the-minute traffic information.
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