City of Cleveland Traffic Signals - 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: Advanced Rail Crossing
Field elements at highway-rail intersections (HRIs) where operational requirements demand advanced features (e.g., where rail operational speeds are greater than 80 miles per hour). Capabilities from the Standard Rail Crossing plus systems which preclude entrance into the intersection when the barriers are activated, additional arriving train information, and detection of blocked intersections.
| 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 determine whether the highway-rail intersection (HRI) is blocked by traffic in the roadway or some other obstruction. | Planned |
| 3 | The field element shall notify the traffic management center and the rail wayside equipment of any intersection blockages, including trapped vehicles or other obstructions. | Planned |
| 4 | 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 |
| 5 | 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 |
| 6 | The field element shall receive track status and arriving train information 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 when a train is expected and/or how long the crossing will be closed. | Planned |
| 7 | 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 |
| 8 | 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 |
| 9 | The field element shall close the highway-rail intersection (HRI) when a train is approaching with enough time for traffic to safely clear the crossing using gates, lights/signs, barriers, and traffic control signals. | Planned |
| 10 | 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 |
| 11 | The field element shall forward rail traffic advisories received from the Wayside Equipment to the traffic management center. | Planned |
| 12 | The field element shall provide approaching train advisories using field-vehicle communications to vehicles approaching the grade crossing. | Planned |
Functional Area: Multimodal Crossing Control
Field elements to monitor and control traffic at multimodal crossings, such as draw bridges and other crossings between highway traffic and other modes; does not include highway-rail intersection.
| ID | Requirement | Status |
|---|---|---|
| 1 | The field element shall include sensors to monitor requests from non-highway traffic to cross at multimodal crossings for specified durations (such as draw bridges and miscellaneous other interference crossings between highway traffic and other modes such as river traffic, aircraft, etc.); the sensors are under center control. | Existing |
| 2 | The field element shall include signals to control traffic at multimodal crossings on surface streets, under center control. | Existing |
| 3 | The field element shall include driver information systems (such as dynamic messages signs, highway advisory radios (HAR), and equipment that controls warning lights and gates) that advise drivers at multimodal crossings, under center control. | Existing |
| 4 | The field element shall provide operational status for the sensors, signals, and driver information systems equipment at multimodal crossings to the center. | Existing |
| 5 | The field element shall provide fault data for the sensors, signals, and driver information systems equipment at multimodal crossings to the center for repair. | Existing |
| 6 | The field element shall forward all requests for right-of-way at multimodal crossings to the controlling center. | Existing |
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 (such as traffic, environmental, and work zone intrusion detection sensors) that provide data and status information to other field element devices (such as dynamic message signs, ramp meters, traffic signals, work zone intrusion alert systems), without center control. | Planned |
| 2 | The field element shall include sensors (such as traffic, environmental, and work zone intrusion detection sensors) that receive control information from other field element devices, without center control. | 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. | Existing |
| 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). | Existing |
| 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. | Existing |
| 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. | Existing |
| 6 | The field element shall return traffic signal controller operational status to the controlling center. | Existing |
| 7 | The field element shall return traffic signal controller fault data to the maintenance center for repair. | Existing |
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 |
| 2 | The field element shall respond to requests for indicator (e.g., signal) priority requests from transit vehicles at intersections, pedestrian crossings, and multimodal crossings. | Planned |
| 3 | The field element shall notify controlling traffic management center and maintenance center that the signal timing has changed based on a signal preemption/priority request to help those centers determine whether a fault detected at the signal is a true malfunction or due to a signal override. | 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). | Existing |
| 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. | Existing |
| 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. | Existing |
| 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. | Existing |
| 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 |
| 9 | The field element shall forward rail traffic advisories received from the Wayside Equipment to the traffic management center. | Planned |