Local 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: Field Management Stations Operation

Supports direct communications between field management stations and the local field equipment under their control.

ID Requirement Status
1 The field management station shall accept configuration information from the center. Near-term
2 The filed management station shall pass data provided by the center to local field devices and report data from the field devices back to the center. Near-term

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. Near-term
2 The field element shall collect, process, and send traffic images to the center for further analysis and distribution. Near-term
4 The field element shall return sensor and CCTV system operational status to the controlling center. Near-term
5 The field element shall return sensor and CCTV system fault data to the controlling center for repair. Near-term

Functional Area: Roadway Environmental Monitoring

Environmental sensors, surface and sub-surface, that collect weather and road surface information. Weather conditions measured include temperature, wind, humidity, precipitation, and visibility. Sensors measure road surface temperature, moisture, icing, salinity, etc.

ID Requirement Status
1 The field element shall include surface and sub-surface environmental sensors that measure road surface temperature, moisture, icing, salinity, and other measures. Medium-term
2 The field element shall include environmental sensors that measure weather conditions including temperature, wind, humidity, precipitation, and visibility. Medium-term
3 The field element's environmental sensors shall be remotely controlled by a maintenance center. Medium-term
4 The field element's environmental sensors shall be remotely controlled by a traffic management center. Medium-term
7 The field element shall provide environmental sensor equipment operational status to the controlling center or maintenance vehicle. Medium-term
8 The field element shall provide environmental sensor equipment fault indication to the controlling center or maintenance vehicle. Medium-term
10 The field element shall provide weather and road surface condition data to centers. Medium-term

Functional Area: Roadway Equipment Coordination

Field elements that control and send data to other field elements (such as environmental sensors that send data to a DMS or coordination between traffic controllers on adjacent intersections), without center control.

ID Requirement Status
1 The field element shall include sensors that provide data and status information to other field element devices, without center control. Near-term
2 The field element shall include sensors that receive configuration data from other field element devices, without center control. Near-term
3 The field element shall include devices that provide data and status information to other field element devices without center control. Near-term
4 The field element shall include devices that receive configuration data from other field element devices, without center control. Near-term

Functional Area: Roadway Incident Detection

Field elements that monitor traffic conditions to identify incidents. It includes traffic detectors that collect traffic flow information and identify unusual traffic conditions and advanced CCTV cameras with built-in incident detection algorithms.

ID Requirement Status
1 The field element shall collect, process, and send traffic images to the center for further analysis and distribution. Near-term
2 The field element shall remotely process video data and provide an indication of potential incidents to the traffic management center. Near-term
3 The field element's video devices shall be remotely controlled by a traffic management center. Near-term
4 The field element shall provide operational status and fault data for the incident detection devices to the traffic management center. Near-term

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. Near-term
2 The field element shall respond to pedestrian crossing requests by accommodating the pedestrian crossing. Near-term
3 The field element shall provide the capability to notify the traffic management center of pedestrian calls and pedestrian accommodations. Near-term
4 The field element shall report the current signal control information to the center. Near-term
6 The field element shall return traffic signal controller operational status to the center. Near-term
7 The field element shall return traffic signal controller fault data to the center. Near-term

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. Near-term

Functional Area: Roadway Signal Priority

Field elements that provide the capability to receive transit vehicle signal priority requests and control traffic signals accordingly.

ID Requirement Status
1 The field element shall respond to signal priority requests from transit vehicles. Near-term

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). Near-term
2 The field element shall include driver information systems that communicate directly from a center to the vehicle radio (such as Highway Advisory Radios) for dissemination of traffic and other information to drivers, under center control. Near-term
4 The field element shall provide operational status for the driver information systems equipment (DMS, HAR, etc.) to the center. Near-term
5 The field element shall provide fault data for the driver information systems equipment (DMS, HAR, etc.) to the center for repair. Near-term

Functional Area: Roadway Work Zone Traffic Control

Field elements in maintenance and construction areas including CCTV cameras, driver information systems (such as DMS), and gates/barriers that monitor and control traffic and provide information directly to drivers in affected areas.

ID Requirement Status
1 The field element shall collect, process, and send work zone images to the center for further analysis and distribution, under center control. Medium-term
2 Under traffic and maintenance center control, the field element shall include driver information systems (such as dynamic messages signs and highway advisory radios) that advise drivers of activity around the work zone through which they are currently passing. Medium-term
3 Under the control of field personnel within maintenance vehicles, the field element shall include driver information systems (such as dynamic messages signs and highway advisory radios) that advise drivers of activity around a work zone through which they are currently passing. Medium-term
4 The field element shall control access to the work zone using automated gate or barrier systems. This includes automated flagger assistance devices that include automated gate arms and other automated gate/barrier systems. Medium-term
5 The field element shall provide operational status for the surveillance (e.g. CCTV), driver information systems, and gates/barriers in work zones to the maintenance center. Medium-term
6 The field element shall provide fault data for the surveillance (e.g. CCTV), driver information systems, and gates/barriers in work zones to the maintenance center for repair. Medium-term