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Outdoor Siren Systems: A review of technology, usage and public response during emergencies



Erica D. Kuligowski, Katrina Wakeman


The NIST Technical Investigation of the 2011 Joplin, MO tornado identified that no widely accepted standards exist for emergency communications in tornado events and more specifically, policies involving the use of outdoor siren systems to alert the public in advance of tornadoes. As a result, siren usage, testing, education and training, and all-clear procedures vary widely across the U.S.; leading to distrust and confusion among community residents surrounding emergency communications. This Technical Note is the first in a series to develop evidence-based guidance for communities on the creation and provision of public alerts, including both outdoor siren (warning) systems and social media (including mobile alerts). It is the hope that this guidance can eventually be used as a basis for standardization, through codes and standards, of the procedures and policies for outdoor siren systems and social media used by communities across the United States. Standardization of emergency communication policies and procedures could occur at multiple levels, including among multiple jurisdictions, state-wide, regionally, or even nationally. This document focuses on outdoor siren systems, specifically presenting a review on technology, usage and public response. First, this document provides an overview on the current status of siren systems in the United States, i.e., the current siren technology available to communities and the ways in which this technology is used in communities across the United States. Second, this document presents a review of the literature on the ways in which people respond to alerting signals (including siren systems) and the current limitations of siren systems in light of these findings. This document ends with a discussion on the key findings and recommendations from the literature on the ways in which to improve current outdoor siren systems, based on the methods by which people receive and process alerts.
Technical Note (NIST TN) - 1950
Report Number


tornadoes, alerts, emergency communication, outdoor siren systems, public response


Kuligowski, E. and Wakeman, K. (2017), Outdoor Siren Systems: A review of technology, usage and public response during emergencies, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 21, 2024)
Created February 6, 2017, Updated November 10, 2018