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DC police use ShotSpotter to analyze sound waves and detect gunshots in real time

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Pistol gun SIG Pro from Wikimedia Commons
Pistol gun SIG Pro from Wikimedia Commons

At a macro level, solving the issue of gun violence is dauntingly difficult. However, police departments are increasingly turning to tools that allow them to address the epidemic in some of America’s most violent cities. ShotSpotter, a gunshot detection system employed by 65 police agencies across the US, just got a shot in the arm when it comes to creating actionable solutions. According to The Washington Post, the network has detected about 39,000 gunshots in Washington, DC over the last eight years. And gunshots are now declining on a year-to-year basis.

The Post reports that the District is served by a network of 300 acoustic sensors across 20 square miles of the city. Each sensor, comprised of microphones, software, and a GPS-linked clock, is designed to pick up the unique "impulsive" sounds of gunplay, ignoring the other sounds of the average city. Sensors work in harmony to detect the time and location of shots fired with precision. According to ShotSpotter senior vice president James Beldock, who the Post interviewed for their report, 10 sensors can determine the location of a gun blast to within two feet. This data is then sent back to city officials, who can then dispatch officers to the afflicted areas, in a process that takes 40 seconds on average.

Detecting gun blasts to within two feet

Of course, no system is perfect. Sounds like fireworks, cars backfiring, and helicopters can all trigger the system. However, these sounds can be filtered out. And the results are encouraging. The gunfire logged by ShotSpotter more than doubles the number of felony gun crimes reported in DC, which has helped officers better respond to violent crime. To wit, the neighborhood surrounding the Clay Terrace housing complex in northeast DC suffered 129 gun-related incidents in 2009. That number dropped to 17 last year.

The report comes only days after last week’s shootings at Los Angeles International Airport, which resulted in the death of a TSA agent and left three other people injured. While ShotSpotter isn't suited for cutting that kind of random violence, it's easy to see it becoming a bigger part of a broader gun crime solution.

Update: An earlier version of this post stated that the ShotSpotter network that serves Washington, DC covers 200 square miles of the city, but that was not correct. It has been updated to reflect the error.