Development of Guidelines for In-roadway Warning Lights

Report No: 05-R10

Published in 2004

About the report:

An illuminated crosswalk is a relatively new traffic control device that is being used throughout the nation to alert approaching motorists to the presence of pedestrians in or about to enter the crosswalk. It consists of a series of lighting units encased in durable housings and embedded in the pavement parallel with the marked crosswalk. The lights are activated by a pedestrian, either by pushbutton or passive detection, and are aimed to flash toward approaching traffic. These light systems are known by many names. In deference to the terminology used in the Manual on Uniform Traffic Control Devices for Streets and Highways, this study refers to them as in-roadway warning lights (IRWLs). The purpose of this research was to develop guidelines for IRWLs that the Virginia Department of Transportation (VDOT) could use statewide to ensure uniformity. The guidelines include both "planning" and "design" guidelines. Planning guidelines focus on when and where IRWLs are needed or justified. Design guidelines focus on design features of IRWLs and their components. The scope of the research was limited to a review of existing guidelines and of experiences with existing IRWLs. Specific tasks undertaken for this research included a literature review, discussions on key issues involving IRWLs with practicing transportation engineering professionals via the Institute of Transportation Engineers' traffic engineering Internet discussion group, and a review of the experiences with several IRWLs in Virginia. A task group of VDOT planners and traffic engineers from the central office and district offices provided oversight; guidance; and, as appropriate, approval of the developed draft guidelines. Based on the findings and conclusions from these three tasks, draft guidelines for IRWLs were compiled and synthesized and then presented to the task group for review and discussion. Revised guidelines were then developed and recommended for pilot implementation.

Disclaimer Statement:The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.


  • Ramkumar  Venkatanarayana, Ph.D., P.E.

Last updated: November 28, 2023

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