Gunshot Detection System Goes Live in San Diego

The system uses audio sensors placed at least 30 feet above street level to determine when and where shootings take place.

by Lyndsay Winkley, The San Diego Union-Tribune / November 23, 2016
A ShotSpotter sensor atop a building. Flickr/Ariel Dovas

(TNS) — Powerful technology installed in four San Diego neighborhoods will inform officers when and where shootings happen, even if no one calls it in.

The San Diego Police Department announced Tuesday it has installed a system that detects gunshots and sends information to police in the southeastern communities of Valencia Park, Skyline, O’Farrell and Lincoln Park. 

The system, called ShotSpotter, uses powerful audio sensors placed at least 30 feet above street level to determine when and where shootings take place. Once the sensors pinpoint where the shots came from, the sound is sent to a review center where someone determines if it was gunfire.

If it is, the incident is forwarded to police. Officers in the field get the location, time of the shooting, the number of rounds. They also can get information such as how many shooters are present and if they’re on the move. 

Police hope the technology will act as a deterrent to gun violence and help officers respond more quickly to gun crimes. Critics are concerned the tool was installed with little to no community input and will contribute to the over-policing of communities of color.

The sensors were installed starting in October. On Tuesday night, officers fired 36 shots to test the system, which went online soon after. Police and ShotSpotter personnel went door-to-door informing community members of the test.

The police department declined to cite specific locations or number of devices.

The system cost $245,000 under a one-year lease agreement. It was mostly paid for with asset forfeiture funds from the District Attorney’s Office. The police department contributed $10,000, also from asset forfeiture funds.

San Diego police Lt. Scott Wahl said police officials chose the four southeastern neighborhoods after researching which communities in San Diego experienced high instances of gun crimes. The neighborhoods selected were high on the list and close in proximity.

“It’s about keeping our streets safe and protecting our communities from gun violence,” Wahl said. “We hope this is a deterrent and prevents gun violence from even occurring, but we want to send a strong message that if someone does decide to shoot a gun, a police officer is going to be notified immediately.”

Wahl said police officials gathered community input during informal meetings with community leaders.

He said the department has been researching the technology for nearly a year, which included speaking with other cities that had implemented the technology and members of San Diego City Council. Councilmember Myrtle Cole, who represents the four communities where the sensors were installed, couldn’t be reached Tuesday night for comment.

The technology is used in more than 90 cities worldwide including New York, Milwaukee and Miami, and has been lauded by some mayors and police officials who have implemented the system.

Statistics curated by SST, Inc., the Newark-based company that created ShotSpotter, shows gunfire in cities that use the system decreased by a median of 13 percent in 2015.

The company produces a report called the National Gunfire Index, which analyzes data from cities that have employed the technology. Of the 46 cities included in their 2015 analysis, 36 saw decreases in rates of gunfire. Nineteen saw decreases greater than 20 percent.

But the system is not without its critics. 

Christie Hill, a senior policy strategist with the American Civil Liberties Union San Diego & Imperial Counties, wrote that the technology may contribute to over-policing in San Diego’s minority neighborhoods. She was also concerned that ShotSpotter was implemented without first getting input from the communities the tool would serve.

“It’s deeply troubling that while the technology and tools of surveillance advance, the color of surveillance remains the same — and basic transparency, oversight, and accountability remain the exception, not the rule,” she wrote in a blog post on the technology.

Hill, and other critics, also raised privacy concerns. ShotSpotter is always sensing for sound. The system is designed to only pick up and pass on noises loud enough to be construed as a gunshot, but sensors retain all detected audio for 72 hours, according to the product’s website. 

Others worry the system will waste officers’ time by sending them to locations where no crime has occurred. A review of ShotSpotter data by Florida newspaper The Miami Herald a year after the system was implemented showed only one in four alerts resulted in a documented crime.

Other jurisdictions who tried the system out eventually cancelled it, claiming it didn’t help officers solve cases.

Wahl said the department will evaluate ShotSpotter at the end of the year to determine whether it was effective and whether it’s worth continuing or expanding.

©2016 The San Diego Union-Tribune. Visit The San Diego Union-Tribune at www.sandiegouniontribune.com. Distributed by Tribune Content Agency, LLC.