Official US Government Icon

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Secure Site Icon

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

The latest general information on the Coronavirus Disease 2019 (COVID-19) is available on the CDC website.

United States Department of Transportation United States Department of Transportation

Acoustical Warning Devices as Emergency Warning Systems, Phase 1

Document Series
Technical Reports
Federal Railroad Administration
Report Number
Subject Emergency Notification Systems, Grade Crossing Technology
Emergency warning, train horn, trespassers, music masking sounds, reaction time, acoustic warning device

This program demonstrated the effectiveness of Acoustical Warning Devices (AWD) as secondary Emergency Warning Signals (EWS). The focus is to warn trespassers of an approaching train, through the development of an emergency warning signals that produce a sense of urgency, are noticeable to trespassers wearing headphones, and uniquely identifiable as train warning signals. Several EWS sounds were developed and evaluated in surveys to assess the participant’s view of the sense of urgency and detectability. Sounds characteristics were identified that enhance detectability.

DOT is committed to ensuring that information is available in appropriate alternative formats to meet the requirements of persons who have a disability. If you require an alternative version of files provided on this page, please contact
Last updated: Tuesday, October 8, 2019