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Office of the Assistant Secretary for Research and Technology
ITS Joint Program Office

Application Areas

Highway Rail Intersection (HRI)


This field-to-field application area covers the interface between (rail) wayside equipment and roadside equipment at a highway rail intersection (HRI), providing the means to support coordinated operation of that equipment. This application area includes the interface to wayside equipment that supports all types of rail, including light-rail transit, rapid-rail transit, commuter rail, freight, and inter-city passenger trains. Similar information exchanges could apply to other types of multimodal crossings (e.g., draw bridges).
This graphic shows the scope of the Field to Field HRI application area.  This scope is described in the preceding text.
National ITS Architecture Interface
This application area includes the interface between the Wayside Equipment terminator (representing the train interface equipment, usually maintained by the railroad) and the Roadway Subsystem (representing the traffic control equipment in the vicinity of the grade crossing). The Wayside Equipment provides notification of arriving trains to the Roadway Subsystem. This could be a simple train presence indication from a track circuit or it could include additional information about the approaching train(s) to assist in deriving approximate arrival time(s) and estimated duration of closure. Additionally, the Wayside Equipment reports its relative health to the Roadway Subsystem. In turn, the Roadway Subsystem adapts traffic control in the vicinity of the grade crossing and provides a real-time indication of its status to the Wayside Equipment. In more advanced applications, the Roadway Subsystem can identify an immobilized vehicle or some other obstruction within the grade crossing and send an indication of intersection blockage to the Wayside Equipment, which could relay this information to the approaching train.

Applicable Standards

In general, the following standards are applicable to Highway Rail Intersection (HRI) deployments. To determine which specific standards are applicable for a deployment you will need to determine which architecture flows will be needed for the Highway Rail Intersection (HRI) piece of your deployment. Contact your local FHWA ITS Division Specialist or an ITS Standards Program Field Support Team contact

Standard Development Status
IEEE 1570-2002 Standard for the Interface Between the Rail Subsystem and the Highway Subsystem at a Highway Rail Intersection; Published
Deployment Resources
Deployment resources can be found in the deployment resources section.