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Traffic Signals
Description
This center-to-field application area covers the interface between a traffic management center and a specific type of roadway equipment that provides signalized intersection control-a local traffic signal controller. Also included in this application area is the interface between the center and an on-street master controller (a field master) that manages a group of local signal controllers. Based upon an analysis of traffic characteristics for a given time and type of day, the traffic management center invokes the appropriate pre-configured traffic signal control system timing plan, including simple pre-timed (fixed) and complex actuated control schemes, which is sent to the field masters and/or traffic signal controllers at the roadside. Traffic sensors that detect traffic flow are also controlled by the traffic management center and are included in this application area.
National ITS Architecture Interface
This application area includes the interface between the Traffic Management Subsystem (TMS) and the traffic signal control equipment and traffic sensors in the Roadway Subsystem (RS). The TMS monitors and manages the traffic signal controllers in the RS, which also includes the field masters, and other ancillary equipment associated with the traffic signal control system, such as traffic sensors. Signal controllers are typically pre-configured locally for safety reasons. Once the initial configuration of the local traffic control is accomplished, a TMS can remotely control traffic signal operation by selecting and invoking a preloaded timing plan, downloading new timing plans, and adjusting other control parameters. The TMS can request operational status of the field devices, including queries on equipment condition. The traffic signal controller and traffic sensor equipment respond with the current operating status information, event logs, alarms and volume reports.
Applicable Standards
In general, the following standards are applicable to Traffic Signals deployments.
To determine which specific standards are applicable for a deployment you will
need to determine which architecture flows will be needed for the Traffic Signals piece of your deployment.
Contact your local FHWA
ITS division specialist or an
ITS Standards Program Field Support Team contact for additional help.
Standards development statuses as of January 23, 2009
Deployment Resources
None
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