RCVW Technical Details: Topics

Welcome to the Rail Crossing Violation Warning (RCVW) Application Demonstration learning center. The content on these pages will help you learn about this project and its role in finding ways to reduce injuries and fatalities at highway-rail grade crossings. The project is sponsored by the Federal Railroad Administration (FRA) and implemented by Michigan Technological University's Rail Program and Battelle. 

This is the RCVW Technical learning module. The RCVW Overview learning module provides background information to explain the needs and objectives of the RCVW demonstration project. Additional information is posted on the FRA Research, Development and Technology pages [RCVW content at FRA was not yet published as of 20 May 2024].

RCVW Project Scope and Intention

The RCVW project developed, tested, and demonstrated the RCVW application to showcase the potential safety benefits of connected vehicle technology for highway users navigating highway-rail intersections. The scope was limited to a demonstration of a prototype connected vehicle application through a small number of tests and is not intended to provide production-ready components or systems. 

In the long run, the expectation is that the RCVW will be a step toward improving grade crossing safety by reducing the number of crashes, injuries and fatalities. It is also expected to facilitate further integration of driver assistance technologies between railway and vehicle stakeholders.

The outcomes of this project assist FRA in their goal toward zero fatalities at the highway-rail intersections and insight collected from the demonstration and related measurements/analysis provide critical information for future system implementation and integration.

Improving safety for all transportation modes will require interagency collaboration. The project provides a general demonstration of connected vehicle safety technologies and a model for the type of multi-agency cooperation with researchers and vendors that can develop transportation safety technologies.

Key Participants and Partners

The key participants for the development and demonstration of the RCVW project are the Federal Railroad Administration (FRA), the Federal Highway Administration (FHWA), the nonprofit science and technology company Battelle Memorial Institute, Michigan Technological University (Michigan Tech), and the commercial marketing company 2nd Sandbar Productions. Additional organizations that would be required for further development and potential production of an operational system would include automobile manufacturers and suppliers, railroad operators and railroad technology developers, state governments and transportation departments, telecommunications industry operators and developers, and additional federal agencies.

Learning Objectives for RCVW Project Overview

Explore additional information about RCVW by following the links below or selecting the tabs at the top of this or any other of the tabbed pages. You can also advance through to the next or previous page by following the links at the bottom left and right of each page.

1. Identify specific system components
2. Describe component functions
3. Rail/road RCVW interaction scenarios (equipment, logic, and signal flow)

Video caption: Demonstration of RCVW technology at the 2022 Michigan Rail Conference in Escanaba, Michigan

From the perspective of the prototype system developer, one of the lessons learned was the fact that a reliable application for enhancing safety at active HRGCs can be built using currently available technology. However, for RCVW to reach its full potential, it requires the commitment of multiple agencies and key stakeholders including the Federal Government, State and local DOTs, Railroad companies, standard development organizations and vehicle manufacturers.

The RCVW project included outreach to industry, government, and academia at several conferences and meetings throughout the United States to help generate interest and foster collaboration among stakeholders.

Extending the Capabilities of Active Warning Devices

Highway-Rail Grade Crossings (HRGC) (also called Highway Rail Intersections (HRI)) are places where road users such as passenger vehicles, trucks, buses, motorcycles, bicycles, and pedestrians are intended to safely cross railroads. The potential for conflict between trains and roadway users is inherent at HRGCs. The high mass of trains and the inherent design of railroads can lead to situations where trains cannot stop quickly enough to avoid road vehicles, so the burden of crash avoidance is placed on the roadway users. 

To help reduce crashes, roadway users are warned about the potential for train presence at an HRGC with passive signs and pavement markings. Some HRGCs have active warning devices. Active signals and barriers rely on signaling systems embedded in the railroad network and communicate with roadway users only when they are within visual or audible range of the HRGC. The traditional active visual warning signals include flashing lights and gates which descend across the roadway. Traditional audible signals include bells and train horns.

The RCVW system can extend the range and specificity of warnings by directly communicating the potential for a train crossing the roadway via in-vehicle visual and audible warnings. As with current passive and active HRGC warnings, the train is not expected to take evasive action and the train operator receives no additional warnings about the presence of roadway users at an HRGC. The only difference between an RCVW-equipped crossing and one without RCVW is that the active crossing warning system also activates the RCVW communications devices. The RCVW-equipped vehicle only receives the signal when the HRGC warning system has been activated and the RCVW equipment relays information about the active signal using wireless data transmission with range limited to around 500 meters (1640 feet). The following video outlines the RCVW components and functionality and describes how it differs from traditional active warning systems.

The RCVW system leverages the traditional grade crossing infrastructure and communications for active warnings. The traditional grade crossing warning system utilizes track circuits to detect a train and activate active warning devices at the grade crossing to warn drivers that a train is approaching. The RCVW system connects a roadside unite (RSU) to the existing active warning devices to determine when to send a signal to the vehicle's on board unit and provide a warning inside the vehicle's cab.

The general sequence of the RCVW operation is described in this block diagram:

Roadside-based Subsystem Equipment

The Figure below represents a block diagram for the RCVW Roadside-based Subsystem. The figure identifies the main components and the associated interconnection that are required.

The RCVW roadside subsystem includes:

• A Roadside Unit Radio (RSU) and its corresponding antennas to transmit the J2735 Standard connected vehicle messages generated by the computer platform.
• A computer platform to integrate, generate and distribute the appropriate RCVW related information to the overall system. 
• Software/firmware designed to provide the required CV related messages such as MAP, SPaT, as well as Global Navigation Satellite System correction data so that the in-vehicle system may determine if and when inform alerts and/or warnings will be presented to the driver .
• A Global Navigation Satellite System receiver and antenna used to generate the GPS correction messages which will be used by the in-vehicle system to enhance the accuracy of  its location. 
• External to the Roadside Subsystem is the Track Signaling System which provides the HRGC activation status for the RCVW. The RCVW system is ready to receive this information via two ways. The source for HRGC activation status may be from a voltage-based detection circuit or an IEEE-1570 compliant device.

The RCVW vehicle-based subsystem includes:

• On-Board Unit Radio (OBU) and corresponding antennas to receive the J2735 standard connected vehicle messages being sent by the Roadside Subsystem. The radio is equipped with a GNSS antenna and module used for time synchronization.
• A computer platform which contains the RCVW algorithm used to process all the information it receives from the RBS along with the in-vehicle GNSS module.
• A Global Navigation Satellite System receiver is used to determine the position and speed of the vehicle.  Satellite signal corrections received from the RBS are used to improve the receiver performance.
• A Driver Visual Interface used for displaying and announcing alerts and warnings to the vehicle driver.
• An Original Equipment Manufacturer Infotainment system could be used instead of the Driver Visual Interface to display and announce alerts and warnings to the vehicle driver.
• Software/firmware designed to process and correlated the received information from the Roadside-based subsystem along with the vehicle speed and location to determine if alerts and warnings to the vehicle driver are required at a given time.

The figure below illustrates the general RCVW concept and functions. The RCVW system uses the roadside unit (RSU) and the on-board unit (OBU) to deliver a message of activated warning devices to the driver inside the vehicle.

1. An equipped vehicle enters the communication range of an RCVW enabled HRGC.
2. The OBU activates the onboard RCVW application.
3. The RSU transmits HRGC-specific data
4. The OBU receives the following HRGC-specific data from the RCVW RSU:

• HRGC warning device operational status (SPAT)
• HRGC geometry (MAP) including the location of the stop lines and the location of the tracks in relation to the road.
• HRGC ID as assigned by the Federal Railroad Administration HRGC inventory
• Global Navigation Satellite System signal corrections

5. The RSU receives a preemption signal from the HRGC controller
6. The RSU transmits the HRGC crossing active information to the OBU.
7. The vehicle OBU RCVW application assesses the situation.

• While the vehicle is approaching and is within the pre-determined range of the HRGC, the Vehicle-based subsystem :
  • Issues an audio and graphic alert via the DVI indicating the activation of the HRGC warning devices.
  • Continually determines the vehicle position relative to the HRGC.
  • Correlates vehicle speed and performance parameters versus position with respect to the HRGC to assess the probability of a safety HRGC protection system violation.
  • Issues urgent audio and graphic warnings via the DVI if an imminent violation is predicted (vehicle not able to adequately stop before reaching the HRGC.
  • Monitors the vehicle sensors for any corrective action (e.g., braking) to determine whether the driver is responding to the in-vehicle warning and extinguish the warning message.
  • Alert messages continue to be issued until the preemption signal is extinguished.

8. When a HRGC Active message has been issued, all roadway vehicles within the effective transmission range of the RSU will continually determine their position with respect to the HRGC. The only roadway users affected by the RCVW safety application are those approaching or stopped at the HRGC. The OBU RCVW application of the affected vehicles will provide the appropriate warnings/alerts, as shown in the demonstration video below.

The actual outcome of RCVW components and functionality is to provide various in-vehicle warnings to drivers traversing HRGCs. On this page, you get to learn the various messages available and experience their functionality in a variety of different situations and scenarios.  

RCVW can provide five core message to the drivers in the vehicle. the following video introduces each of these messages and their objective:

We have developed three narrated animations to illustrate situations when each of the messages may be displayed. You can access these animations from the links below:

Now that you have learned the different messages and functionalities available in the RCVW, we invite you to take a look at them in action through our series of demonstration videos produced in the field conditions. We've produced several examples of each scenario for exploration. it should be noted that these videos were all produced in collaboration with roadway and railway authorities and were done under controlled environment with safety protocols in place. These videos offer you an opportunity to explore the different ways drivers can experience RCVW.