Portsmouth Traffic Signals - Roadway Functionality
Subsystem Description
The Roadway Subsystem (RS) includes the equipment distributed on and along the roadway that monitors and controls traffic and monitors and manages the roadway itself. Equipment includes traffic detectors, environmental sensors, traffic signals, highway advisory radios, dynamic message signs, CCTV cameras and video image processing systems, grade crossing warning systems, and freeway ramp metering systems. HOV lane management, reversible lane management functions, and barrier systems that control access to transportation infrastructure such as roadways, bridges and tunnels are also supported. This subsystem also provides the capability for environmental monitoring including sensors that measure road conditions, surface weather, and vehicle emissions. In adverse conditions, automated systems can be used to apply anti-icing materials, disperse fog, etc. Work zone systems including work zone surveillance, traffic control, driver warning, and work crew safety systems are also included. To enhance security, safeguard systems such as blast shields, exhaust systems and other automated and remotely controlled systems to protect transportation infrastructure is also provided. In advanced implementations, this subsystem supports automated vehicle safety systems by safely controlling access to and egress from an Automated Highway System through monitoring of, and communications with, AHS vehicles. Intersection collision avoidance functions are provided by determining the probability of a collision in the intersection and sending appropriate warnings and/or control actions to the approaching vehicles.
Functional Area: Roadway Signal Controls
Field elements including traffic signal controllers for use at signalized intersections; also supports pedestrian crossings.
| ID | Requirement | Status |
|---|---|---|
| 1 | The field element shall control traffic signals under center control. | Existing |
| 4 | The field element shall report the current signal control information to the center. | Existing |
| 5 | The field element shall report current preemption status to the center. | Existing |
| 6 | The field element shall return traffic signal controller operational status to the center. | Existing |
| 7 | The field element shall return traffic signal controller fault data to the center. | Existing |
Functional Area: Roadway Signal Preemption
Field elements that receive signal preemption requests from approaching emergency vehicles and overrides the current operation of the traffic signals
| ID | Requirement | Status |
|---|---|---|
| 1 | The field element shall respond to signal preemption requests from emergency vehicles. | Existing |
Functional Area: Roadway Signal Priority
Field elements that provide the capability to receive transit vehicle signal priority requests and control traffic signals accordingly.