VAST Regional ITS Architecture

Roadway Signal Control Functional Area

Description

'Roadway Signal Control' includes the field elements that monitor and control signalized intersections. It includes the traffic signal controllers, detectors, conflict monitors, signal heads, and other ancillary equipment that supports traffic signal control. It also includes field masters, and equipment that supports communications with a central monitoring and/or control system, as applicable. The communications link supports upload and download of signal timings and other parameters and reporting of current intersection status. It represents the field equipment used in all levels of traffic signal control from basic actuated systems that operate on fixed timing plans through adaptive systems. It also supports all signalized intersection configurations, including those that accommodate pedestrians. In advanced, future implementations, environmental data may be monitored and used to support dilemma zone processing and other aspects of signal control that are sensitive to local environmental conditions.

Included In

WSDOT SWR Field Equipment
Clark County Field Equipment
City of Vancouver Field Equipment
City of Camas Field Equipment

Functional Requirements

ID	Requirement
01	The field element shall control traffic signals under center control.
02	The field element shall respond to pedestrian crossing requests by accommodating the pedestrian crossing.
03	The field element shall provide the capability to notify the traffic management center of pedestrian calls and pedestrian accommodations.
04	The field element shall report the current signal control information to the center.
05	The field element shall report current preemption status to the center.
06	The field element shall return traffic signal controller operational status to the center.
07	The field element shall return traffic signal controller fault data to the center.
08	The field element shall report current transit priority status to the center.
09	The field element shall report current intersection signal timing information to roadside equipment for transmission to connected vehicles.
10	The field element shall receive request for transit vehicle signal priority.
11	The field element shall receive request for commercial vehicle signal priority.
12	The field element shall report current commercial vehicle priority status to the center.
13	The field element shall provide to roadside equipment the intersection geometry and signal phase movement information including phase and timing information, alarm status, and priority/preempt status.
14	The field element shall provide data to the Connected Vehicle Roadside Equipment.
15	The field element shall receive requests for emergency vehicle signal preemption.
16	The field element shall receive request for signal change from an emissions/environmental field device.
17	The field element shall report current emissions/environmental priority status to the center.