Police / Fire

Gunshot detection system gets mixed reviews nationally

The Shotspotter acoustic gunshot detection system will eventually come back to Hollister City Council for a vote. If approved, the first year will cost nearly $50,000 to monitor one square mile of the city. 

Editor’s note: This article was updated to remove information that San Jose was using ShotSpotter. That was incorrect. Last updated Feb. 15 at 11:04 a.m.


When a representative for ShotSpotter, a Fremont-based company that claims its technology helps police detect where gunshots are coming from to accelerate response time to shootings, made his sales pitch to the Hollister City Council on Jan. 17, Councilwoman Dolores Morales questioned the project and asked that the process slow down so staff could look at other companies that provide similar products. 

Mayor Mia Casey, along with Councilmembers Rick Perez and Tim Burns, indicated they were ready to move forward to approve the technology for $50,000 a year for one-square-mile of coverage. Councilmember Rolan Resendiz was not present. City Manager Brett Miller said there is no date set to bring ShotSpotter back to the council for consideration. Hollister Police Chief Carlos Reynoso told BenitoLink on Feb. 8 that he is still reaching out to other city police departments researching the system.

The proposed coverage includes the west and northeast parts of the city. (see map) 

The accumulative area that ShotSpotter would cover would be about one square mile. The area is bordered by Buena Vista Road, Miller Road, South Street and Chappell Road. Image courtesy of Hollister Police.
The accumulative area that ShotSpotter would cover would be about one square mile. The area is bordered by Buena Vista Road, Miller Road, South Street and Chappell Road. Image courtesy of Hollister Police.
Image courtesy of Hollister Police.
Image courtesy of Hollister Police.

According to ShotSpotter, the technology uses a network of acoustic sensors to accurately identify and locate the source of gunfire. The data then is analyzed by staff at ShotSpotter’s review center before confirming it’s a gunshot and publishing it for police. The system is designed, the company claims, to help law enforcement respond quickly to active-shooter situations, and to reduce crime and shootings in general. 

The main selling point of ShotSpotter is its accuracy. The system reportedly is able to detect gunshots with a high degree of precision, 97% accuracy, and can pinpoint the source of the gunfire to within a few feet. 

ShotSpotter says its system can also be used to respond to other types of gunfire, such as celebratory shots during holidays or gang-related shootings, and that it helps reduce crime in general by providing real-time information about gunfire in a given area, allowing police to deploy resources more intelligently.

How ShotSpotter works. Image from ShotSpotter.

Despite its stated benefits, ShotSpotter is not without its drawbacks, the first being its cost. According to a technology study published in Police Chief magazine, acoustic gunshot detection systems (AGDS) such as ShotSpotter, “leads to a substantial increase in the total number of ‘shots fired’ calls, costing departments additional resources in response time. Whereas AGDS calls were handled more quickly overall, there is no statistical difference in the time it took officers reaching the scene.” 

The report also stated, “Typical vendor costs for AGDS are around $65,000 to $90,000 per mile per year, but these vendor costs do not account for the increases in call volume agencies may experience, nor for any losses of efficiency in the response.” 

A 2021 study conducted by the MacArthur Justice Center of over 40,000 dispatches in an under two-year period in Chicago found that 89% of dispatches resulted in no gun-related crime, and 86% resulted in no reports of crime at all.

The American Civil Liberties Union, which has expressed concerns about the use of the technology, argues that it raises privacy concerns, as it records and collects data on all sounds in a given area, not just gunfire. 

The ACLU claims ShotSpotter is deployed overwhelmingly in communities of color, which “already disproportionately bears the brunt of a heavy police presence. The police say they pick neighborhoods for deployment based on where the most shootings are, but there are several problems with that.”

ACLU also claimed that “ShotSpotter false alarms send police on numerous trips into communities for no reason and on high alert expecting to potentially confront a dangerous situation.”  

While some raise concerns about gunshot detection technology, Oakland police say it has been beneficial for its department. 

According to the Oakland Police Department spokesperson Kim Armstead, the Oakland City Council authorized the ShotSpotter system in July 2006.  From 2016 through 2022, the department has paid $4,600,842 for ShotSpotter, she said. 

OPD chose to install the sensors in areas most prone to gunshots based upon historical data. Amstead said in 2021 there were 8,922 unique gunshot incidents and 99% were not called in to 911. Without ShotSpotter, she said, OPD would not have responded “in a timely fashion.”

The police department releases a weekly ShotSpotter activity report.

“Staff believe that there were many more cases where OPD responded to activations and found shooting victims—and where critical medical attention was provided,” she said. “The 86 cases (76 injury cases) are the ones where OPD and ShotSpotter staff can conclusively cite the response to the ShotSpotter activations.”

ShotSpotter claims it has deployed its system in 135 cities nationwide but does not list them or how many there are in California. BenitoLink found their systems are in Bakersfield, Salinas, Fresno, San Francisco, Oakland, Richmond, San Pablo, and Stockton. The Vallejo City Council voted in June 2022 to delay approving the system after the city’s police chief asked for 80 to 100 of the devices to be installed in the city.

San Francisco has had ShotSpotter since 2012. In a surveillance impact study (see PDF), SFPD found that, “Only 15% of gunshot incidents in SF have an accompanying 911 call. Without ShotSpotter there would be no police response to 85% of gun crime representing over 850 incidents. However, with ShotSpotter, virtually all incidents are captured with an exact location enabling the department to better protect and serve the community.” 

The study also found there were both financial and time savings. 

“If a 911 caller reports a gunshot incident, it usually takes several minutes to capture and relay the information to officers often with imprecise data on the exact location. With ShotSpotter, officers receive alerts within 60 seconds of trigger pull with closest address data enabling a faster response to a crime scene to potentially save victims. Officers can approach a crime scene more safely with ShotSpotter alerts knowing the precise location and time of the event and whether there are multiple shooters or high-capacity weapons being used.” 


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John Chadwell

John Chadwell is a freelance photojournalist with additional experience as a copywriter, ghostwriter, scriptwriter, and novelist. He is a former U.S. Navy Combat Photojournalist and is an award-winning writer, having worked for magazine, newspapers, radio and television. He has a BA in Journalism and Mass Communications from Chapman University and graduate studies at USC Cinema School. John worked as a scriptwriting consultant, and his own script, "God's Club," was produced and released in 2016. He has also written eight novels, ranging from science fiction to true crime, which are sold on Amazon. To contact John Chadwell, send an email to: [email protected]