City of Fresno Vehicle Detection Systems - 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 |
Functional Area: Roadway Data Collection
Field elements to collect traffic, road, and environmental conditions information for use in transportation planning, research, and other off-line applications. Includes the sensors, supporting roadside infrastructure, and communications equipment.
| ID | Requirement | Status |
|---|---|---|
| 1 | The field element shall collect traffic, road, and environmental conditions information. | Existing |
| 2 | The field element shall include the sensors and supporting roadside devices that sense, collect, and send traffic, road, and environmental conditions information to a center for archival. | Existing |
| 3 | The field element shall collect sensor status and sensor faults from roadside equipment and send it along with the recorded data to a center for archival. | Existing |
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 |
|---|---|---|
| 2 | The field element shall include environmental sensors that measure weather conditions including temperature, wind, humidity, precipitation, and visibility. | Planned |
| 3 | The field element's environmental sensors shall be remotely controlled by a maintenance center. | Planned |
| 6 | The field element's environmental sensors shall be remotely controlled by a maintenance and construction vehicle. | Planned |
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.
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.
Functional Area: Roadway Probe Data Communications
Field elements that collect probe data from vehicles using short range communications.
| ID | Requirement | Status |
|---|---|---|
| 1 | The field element shall communicate with passing vehicles for traffic data link time calculations and send collected data to the controlling center; identification will be removed to ensure anonymity. | Planned |
| 2 | The field element shall communicate with on-board equipment on passing vehicles to collect current vehicle position, speed, and heading and a record of previous events (e.g., starts and stops, link travel times) that can be used to determine current traffic conditions. | Planned |
| 3 | The field element shall communicate with on-board equipment on passing vehicles to collect current status information and a record of previous events (e.g., temperature, wiper status, headlight status, traction control system status) that can be used to determine road and surface weather conditions. | Planned |
| 4 | The field element shall communicate with on-board equipment on passing vehicles to collect vehicle trip information (e.g., origin and destination information, travel times) that can be used to support transportation planning. | Planned |
| 5 | The field element shall communicate with on-board equipment on passing vehicles to collect a history of precise positioning information that can be used to derive or verify accurate roadway geometry and lane features for use by map update providers. | Planned |
| 6 | The field element shall aggregate and forward collected probe information to the center. | Planned |
| 7 | The field element shall provide roadside equipment operational status to the center. | Planned |
| 8 | The field element shall provide roadside equipment fault indication to the center for repair. | Planned |
Functional Area: Roadway Short Range Traveler Information Communications
Field elements that distribute information to in-vehicle equipment. The information provided may be determined locally or under the control of a center.
| ID | Requirement | Status |
|---|---|---|
| 1 | The field element shall distribute traveler information including traffic and road conditions to passing vehicles using short range communications, under center control. | Planned |
| 2 | The field element shall distribute advisory information, such as evacuation information, wide-area alerts, incident information, work zone intrusion information, and other special information to passing vehicles using short range communications, under center control. | Planned |
| 3 | The field element shall distribute indicator and fixed sign information, including static sign information (e.g., stop, curve warning, guide signs, service signs, and directional signs) and dynamic information (e.g., current signal states and local conditions warnings identified by local environmental sensors) to equipment on-board vehicles under center control. | Planned |
| 4 | The field element shall return system operational status to the controlling center. | Planned |
| 5 | The field element shall return system fault data to the maintenance center for repair. | Planned |