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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation
FHWA Highway Safety Programs

Recording Devices for Interconnected Grade Crossing and Intersection Signal Systems: An Informational Report

FHWA Safety Program


October 12, 2012

Quality Assurance Statement

This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the data published herein. The contents do not necessarily reflect the official view or policies of the Federal Highway Administration (FHWA). The U.S. Government assumes no liability for the use of the information contained in this document. This report does not constitute a standard, specification, or regulation.


The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers' names appear in this report only because they are considered essential to the objective of the document.

Quality Assurance Statemen

The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.



Term Definition
AHWS Automatic Highway Warning System
AREMA American Railway Engineering and Maintenance-of-Way Association
ATC Advanced Transportation Controller
CFR Code of Federal Regulations
DIR Direction of Train
FHWA Federal Highway Administration
FRA Federal Railroad Administration
HRI Highway Railroad Intersection
ICO Island Circuit Occupied
IEEE Institute of Electrical and Electronics Engineers
IMSA International Municipal Signal Association
LTI Long Term Obstacle Indicator
MUTCD Manual on Uniform Traffic Control Devices
NEMA National Electrical Manufacturers Association
NGD Entrance Gate Down
NGP Entrance Gate Present
NGU Entrance Gate Up
NTSB National Transportation Safety Board
PEA Preemption Warning Active
PER Preemption Relay
PSP Product Safety Plan
RSO Roadway System Operational
RSPP Railroad Safety Program Plan
SO System Operational (railroad)
TPD Train Presence Detection
USDOT United States Department of Transportation
VAS Vehicle Arrestor Barrier Status
VP Vehicle Presence
WSA Warning System Active
XGD Exit Gate Down
XGP Exit Gate Present
XGU Exit Gate Up
XR Grade Crossing Relay