Municipal ITS Field Equipment - Roadway Subsystem Functionality
Subsystem Description
This subsystem 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. | Planned |
| 2 | The field element shall collect, process, and send traffic images to the center for further analysis and distribution. | Planned |
| 4 | The field element shall return sensor and CCTV system operational status to the controlling center. | Planned |
| 5 | The field element shall return sensor and CCTV system fault data to the controlling center for repair. | Planned |
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 at intersections and on main highways for urban and rural areas, under center control. | Planned |
| 2 | The field element shall collect pedestrian images and pedestrian sensor data, and respond to pedestrian crossing requests via display, audio signal, or other manner. | Planned |
| 3 | The field element shall provide the capability to notify the traffic management center that a pedestrian has requested right-of-way and when the request was or will be granted (request for right-of-way). | Planned |
| 4 | The field element shall monitor operation of traffic signal controllers and report to the center any instances in which the indicator response does not match that expected from the indicator control information. | Planned |
| 5 | The field element shall monitor operation of traffic signal controllers and report to the center any instances in which the indicator response does not match that expected from known indicator preemptions. | Planned |
| 6 | The field element shall return traffic signal controller operational status to the controlling center. | Planned |
| 7 | The field element shall return traffic signal controller fault data to the maintenance center for repair. | Planned |
Functional Area: Roadway Signal Priority
Field elements that provide the capability to receive vehicle signal priority requests and control traffic signals accordingly.
| ID | Requirement | Status |
|---|---|---|
| 1 | The field element shall respond to requests for indicator (e.g., signal) preemption requests from emergency vehicles at intersections, pedestrian crossings, and multimodal crossings. | Planned |
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). | Planned |
| 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. | Planned |
| 3 | The field element shall include pedestrian information systems under center control (e.g. warning pedestrians of a potential hazard, or providing mandatory instructions as to the availability of pedestrian access). | Planned |
| 4 | The field element shall provide operational status for the driver information systems equipment (DMS, HAR, etc.) to the center. | Planned |
| 5 | The field element shall provide fault data for the driver information systems equipment (DMS, HAR, etc.) to the center for repair. | Planned |
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. | Planned |
| 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. | Planned |
| 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. | Planned |
| 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. | Planned |
| 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. | Planned |
Functional Area: Standard Rail Crossing
Field elements at highway-rail intersections (HRIs) where operational requirements do not dictate advanced features (e.g., where rail operational speeds are less than 80 miles per hour). Includes traditional HRI warning systems augmented with other standard traffic management devices.
| ID | Requirement | Status |
|---|---|---|
| 1 | The field element shall collect and process, traffic sensor data in the vicinity of a highway-rail intersection (HRI). | Planned |
| 2 | The field element shall monitor the status of the highway-rail intersection (HRI) equipment, including both the current state and mode of operation and the current equipment condition, to be forwarded on to the traffic management center. | Planned |
| 3 | The field element shall monitor the status of the highway-rail intersection (HRI) equipment, including both the current state and mode of operation and the current equipment condition, to be forwarded on to the rail wayside equipment. | Planned |
| 4 | The field element shall receive track status from the rail wayside equipment that can be passed on to the traffic management center. This may include the current status of the tracks and whether a train is approaching. | Planned |
| 5 | The field element shall collect pedestrian images and pedestrian sensor data, and respond to pedestrian crossing requests via display, audio signal, or other manner. | Planned |
| 6 | The field element shall control the dynamic message signs (DMS) in the vicinity of a highway-rail intersection (HRI) to advise drivers, cyclists, and pedestrians of approaching trains. | Planned |
| 7 | The field element shall close the highway-rail intersection (HRI) when a train is approaching using gates, lights/signs, barriers, and traffic control signals. | Planned |
| 8 | The field element shall support the integrated control of adjacent traffic signals to clear an area in advance of an approaching train and to manage traffic around the intersection. | Planned |