Physical Object: ITS Roadway Equipment

Roadway Variable Speed Limits

Overview
Requirements
Information Flows
Standards

Overview

'Roadway Variable Speed Limits' includes the field equipment, physical overhead lane signs and associated control electronics that are used to manage and control variable speed limits systems. This equipment monitors traffic and environmental conditions along the roadway. The system can be centrally monitored and controlled by a Traffic Management Center or it can be autonomous, calculating and setting suitable speed limits, usually by lane. This application displays the speed limits and additional information such as basic safety rules and current traffic information to drivers.

This functional object is included in the "ITS Roadway Equipment" physical object.

This functional object is included in the following service packages:

This functional object is mapped to the following Functional View PSpecs:

Requirements

#	Requirement
01	The field element shall monitor traffic and environmental conditions along the roadway.
02	The field element shall autonomously calculate and set variable speed limits based on current conditions by lane.
03	The field element shall receive commands from the controlling center that establish speed limits by lane.
04	The field element shall display the current speed limits per lane to drivers.
05	The field element shall display additional information such as basic safety rules and current traffic information to drivers.
06	The field element shall collect operational status of the variable speed limit field equipment and report the operational status to the controlling center.
07	The field element shall monitor and report faults to the controlling center.
08	The field element shall display suggested harmonized speed per lane to drivers.
09	The field element shall send suggested speed per lane to the RSE for transmittal to connected vehicles.

Information Flows

Source	Flow	Destination
ITS Roadway Equipment	driver information	Commercial Vehicle Driver
ITS Roadway Equipment	driver information	Driver
ITS Roadway Equipment	driver information	Emergency Personnel
ITS Roadway Equipment	driver information	Light Vehicle Driver
ITS Roadway Equipment	driver information	Maint and Constr Vehicle Operator
ITS Roadway Equipment	driver information	Transit Vehicle Operator
ITS Roadway Equipment	variable speed limit coordination	Other ITS Roadway Equipment
ITS Roadway Equipment	variable speed limit status	Traffic Management Center
Other ITS Roadway Equipment	environmental sensor coordination	ITS Roadway Equipment
Other ITS Roadway Equipment	traffic detector coordination	ITS Roadway Equipment
Other ITS Roadway Equipment	variable speed limit coordination	ITS Roadway Equipment
Traffic Management Center	variable speed limit control	ITS Roadway Equipment

Standards

Currently, there are no standards associated with the functional object itself though the interfaces may have standards associated with them.