U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Diagram shows that the vehicle detection system detects vehicles, then sends a signal to detector amplifiers, which transmits the data to an industrial personal computer (dimensions 7 inches by 7 inches by 10 inches), which then sends data to the digital input/output interface. From here, direction is sent to the traffic control system via a signal controller, which controls the signal head. Conflicting call signals are sent back to the digital input/output interface for decisionmaking to force or hold the signal.
Diagram shows the positioning of an advanced dilemma-zone detection system on a roadway. On the approach to a signalized intersection, a D-CS Detector trap is set approximately 800 to 1,000 feet from the stop line. Segment A is furthest from the intersection and defines the dilemma zone of a vehicle traveling at 70 mph. Segment B is on the approach to an intersection and defines the dilemma zone of a vehicle traveling at 25 mph. Located right before the stop bar are stop line detectors in each lane at the intersection.