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Technological Approaches to Controlling Random Gunfire: Results of a Gunshot Detection System Field Test

NCJ Number
Policing: An International Journal of Police Strategies & Management Volume: 25 Issue: 2 Dated: 2002 Pages: 345-370
Cory Watkins; Dennis Rogan; James Frank; Lorraine Green Mazerolle
Date Published
26 pages

Using a quasi-experimental design methodology, this study conducted a controlled field evaluation of the ShotSpotter gunshot-location technology in Redwood City, California.


Random gunshot-location technology was implemented in Redwood City in 1997. This technology was designed and manufactured by Trilon Technology, and it is intended to identify the location and time of gunfire in a specified target area through a series of acoustic sensor modules. The ShotSpotter system consists of acoustic sensors located in the target area, a central computer located in the police department's dispatch center, and gunshot detection and location identification software. The system stores all waveforms for every detected gunfire event and 6 seconds of audio from each detecting acoustic sensor. The primary purpose of the ShotSpotter field trial was to determine its utility as a problem-oriented policing tool. Firing test blanks under controlled field trial conditions in order to test the system's performance was approved by the Redwood Police Department in June 1997. The test results indicate that overall the ShotSpotter system was able to detect gunshots in 81 percent of the field trial events (25 of 31 shooting events) and triangulate (locate) gunshots in 84 percent of the field trial events (26 of 31 shooting events) within an average margin of error of 41 feet. The paper concludes with a discussion of the policy implications of using gunshot-detection technology as a problem-solving tool to detect, reduce, and prevent incidences of random gunfire. 2 figures, 5 tables, 8 notes, and 42 references