ITS

ITS extends into applications that can be implemented at railroad crossings and within vehicles which will affect traffic signal preemption. Typically, trains have the ROW at crossings, and the crossings are managed to maximize safety of all users while minimizing delay to roadway traffic. This involves the coordination of railroad active safety devices with highway traffic signals, as well as the dissemination of crossing status information to aid in route planning. The advancement of ITS applications can enhance these capabilities for all parties involved. 166ITS National Architecture and User Service 30 Per FHWA, “National ITS Architecture (also “national architecture”) means a common framework for ITS interoperability. The National ITS Architecture comprises the logical architecture and physical architecture which satisfy a defined set of user services. The National ITS Architecture is maintained by the USDOT and is available on the DOT website.(62) The FHWA, in conjunction with FRA, has developed “User Service 30” to describe the ITS applications that relate to the highway ‑rail crossing. These ITS applications have been defined in the National ITS Architecture, which is a framework for developing integrated transportation systems. The National ITS Architecture defines a set of “subsystems,” “terminators,” and “architecture flows” that describe the transfer of information between ITS systems. Subsystems are the building blocks of the National ITS Architecture that perform the ITS functions identified in 33 user services (which include the highway ‑rail crossing user service). Terminators are systems that interface with the ITS systems. Architecture flows are the definition of the information that is passed between subsystems or between subsystems and terminators. In the context of the National ITS Architecture, highway ‑rail crossing functions are identified with the following three interfaces (refer to Figure 66):

•Roadway subsystem and the wayside equipment terminator

•Traffic management subsystem (TMS) and the rail operations terminator

•Highway ‑rail intersection data, traffic management to roadway Figure 66. Highway Rail Intersection Interface Overview Source: The National Architecture for ITS, USDOT. 167Roadway subsystem and the wayside equipment terminator. The roadway subsystem represents ITS field equipment, including traffic control signal controllers. The wayside equipment terminator represents train interface equipment (usually) maintained and operated by the railroad and (usually) physically located at or near a crossing. The roadway subsystem interface with the railroad wayside equipment will provide crossing status and blockage notification to wayside equipment and, conversely, real-time information about the approach (actual or predicted) of a train to the roadway subsystem. The interface operates as follows:

•The roadway subsystem sends the real-time crossing status to the wayside equipment. This includes a confirmation that the crossing is closed (gates are down) and that trains may proceed at full authorized speed.

•The roadway subsystem also sends a real-time indication of intersection blockage. This message would be used to provide the information needed by the wayside equipment to alert the train to reduce speed or stop.

•The wayside equipment provides a real-time indication of its operational status via the track status flow. This would alert the roadside equipment to possible failures or problems in the wayside equipment. The track status flow also includes the simple binary indication of a train approaching, which is currently used when traffic control signal controller units are interconnected with the wayside equipment.

•In future implementations, the wayside equipment would provide expected time of arrival and length of closure via an arriving train information flow. TMS and the rail operations terminator. The interface between the rail operations terminator and TMS provides for the exchange of management or near real-time data between these two key functions.

•The rail operations function will send information to the TMS to support forecasting of crossing closures. This includes train schedules and crossing maintenance schedules. In addition, the rail operations function will send to the TMS information about rail incidents that may impact vehicle traffic. This latter information would be in near real time; other schedule information would be provided on a periodic basis (such as daily).

•The TMS would notify the rail operations function in near real time about equipment failure, intersection blockage, or other incident information (such as a nearby hazardous material spill). The TMS would also send information about planned maintenance activities occurring at or near the crossing that would impact the railroad ROW. Roadway subsystem and TMS. Beginning in 2011, FRA began researching connected vehicle concepts appropriate for highway-rail crossings. The primary objective of this research is to explore the feasibility of in-vehicle safety concepts capable of providing an alert of an approaching train to a highway vehicle approaching a highway-rail crossing. The technology is intended to be deployed at any highway ‑rail crossing where benefit would be accrued by increasing situational awareness to minimize safety related incidents or improving the flow of roadway traffic. 168A set of the following potential scenarios were initially identified and evaluated for future implementation: Highway-rail crossing equipped with active warning devices. Connected vehicle roadside equipment is activated by the highway-rail crossing signaling system preemption signal by means of a hardwire interconnection. Approaching highway vehicles received alerts over the connected vehicle Dedicated Short Range Communications (DSRC) communications channel. Trains equipped with advanced technology. This scenario would utilize emerging train positioning technology. Connected vehicle roadside equipment could receive train location information over the 220MHz communications network and provide alerts to approaching highway vehicles over the connected vehicle DSRC communications channel. Highway-rail crossing not equipped with active warning devices. A train is equipped with connected vehicle onboard equipment that allows it to transmit over a DSRC communications channel directly with highway vehicles. This is the only scenario that is dependent upon the installation of connected vehicle technology on trains. To this end, FRA has been exploring the feasibility of the first scenario and has developed concept of operations and system requirements documents to support this approach. Proof-of- concept testing was performed in 2017 on a DSRC-based platform, but the effort remains in the exploratory phase.

Standard 1570

The Institute of Electrical and Electronics Engineers (IEEE) empaneled a working group that developed IEEE Standard 1570, “Standard for the Interface Between the Rail Subsystem and the Highway Subsystem at a Highway Rail Intersection.” (63) This standard was developed to coordinate information transfer between the two with emphasis on digital data communication and to enable interoperability among the various types of equipment.