Public-Private Toll Roadway Devices - 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 Basic Surveillance

Field elements that monitor traffic conditions using loop detectors and CCTV cameras.

ID Requirement Status
1 The field element shall collect, process, digitize, and send traffic sensor data (speed, volume, and occupancy) to the center for further analysis and storage, under center control. Existing
2 The field element shall collect, process, and send traffic images to the center for further analysis and distribution. Existing
4 The field element shall return sensor and CCTV system operational status to the controlling center. Existing
5 The field element shall return sensor and CCTV system fault data to the controlling center for repair. Existing

Functional Area: Roadway Emissions Monitoring

Emissions and air quality sensors that collect vehicular emissions and area-wide air quality data.

ID Requirement Status
2 The field element shall include air quality sensors, often distributed geographically, that detect area-wide levels of pollution, under center control. Existing
3 The field element shall analyze collected vehicle emissions data against reference data to determine whether or not a vehicle is violating the acceptable levels of emissions, and shall return this analysis to a center for possible enforcement action. Existing
4 If the emissions level detected by the emissions sensor indicates a vehicle is violating the acceptable levels of emissions, the field element shall provide the capability to display summary emissions information or warnings to passing drivers via a driver information system (such as portable messages signs, field to vehicle communications to in-vehicle signing systems, etc.). Existing
5 The field element shall provide emissions sensor equipment operational status to the center. Existing
6 The field element shall provide emissions sensor equipment fault indication to the center for repair. Existing

Functional Area: Roadway Reversible Lanes

Traffic sensors, surveillance, and automated reversible lane equipment and lane control signals to control traffic in reversible lanes.

ID Requirement Status
1 The field element shall monitor traffic in reversible lanes, including wrong-way vehicles, using sensors and surveillance equipment under center control. Existing
2 The field element shall include automated reversible lane equipment and driver information systems (such as lane control signals) that control traffic in reversible lanes on surface streets, under center control. Existing
3 The field element shall include automated reversible lane equipment and driver information systems (such as lane control signals) that control traffic in reversible lanes on freeways, under center control. Existing
4 The field element shall provide operational status for the reversible lane field equipment to the center. Existing
5 The field element shall provide fault data for the reversible lane field equipment to the center. Existing

Functional Area: Roadway Traffic Information Dissemination

Driver information systems, such as dynamic message signs and Highway Advisory Radio (HAR).

ID Requirement Status
1 The field element shall include dynamic messages signs for dissemination of traffic and other information to drivers, under center control; the DMS may be either those that display variable text messages, or those that have fixed format display(s) (e.g. vehicle restrictions, or lane open/close). Existing
4 The field element shall provide operational status for the driver information systems equipment (DMS, HAR, etc.) to the center. Existing
5 The field element shall provide fault data for the driver information systems equipment (DMS, HAR, etc.) to the center for repair. Existing