The San Jose Police Department has launched a six-month pilot program to determine the efficacy of a gunshot detection system.

The goal of the gunshot detection system is to reduce violence in the city and make it easier and quicker for police to locate where and when a gun was shot.

The program is launching in the Cadillac/Winchester neighborhood near West San Jose and the Clemence/Owsley neighborhood in East San Jose.

It works by using a portable acoustic signal identifier and alerting device that continually monitors the ambient environmental audio to detect the location of a gunshot event.

If a gunshot is detected, an alert is sent to the police dispatch center within seconds, according to San Jose police.

A study by the National Institute of Justice found that one brand of the detection software, called ShotSpotter, was able to accurately detect 80 percent of shots fired within a square mile testing area. ShotSpotter also had a faster police response time by 10 minutes on average.

San Jose is using the V5 Systems OnSound gunshot detection which has a 90 percent accuracy in a 250-foot range for its gunshot detection devices.

YouTube video
Product promotional video for V5 Systems OnSound gunshot detection equipment. (Video courtesy of V5 Systems/YouTube)

The system also has cameras and license plate readers so that it can capture other crime-related evidence.

Both the system and the cameras are continuously running but not continuously monitored, police said. The video would only be accessed in the event of a crime.

But the constant surveillance makes some San Jose residents uncomfortable.

Ethan Dodge from the Citizens Privacy Coalition of Santa Clara County worries how it will be used.

“Due to racism in policing, so many surveillance technologies are placed in neighborhoods with large Black and Brown populations. Overly surveilled neighborhoods are overly policed neighborhoods,” Dodge said. “So, if the algorithm incorrectly classifies a bang as a gunshot and sends police into a neighborhood they already have implicit bias against and worse, they believe someone is armed, that situation is not going to end well.”

He also noted that even if the technology is effective in distinguishing a gunshot from a loud bang like a firework, there is still a 10 percent change that it is wrong.

“When you’re dealing with a police force who has taken 19 lives in the past 5 years, those aren’t good odds,” Dodge added.

“(I)f the algorithm incorrectly classifies a bang as a gunshot and sends police into a neighborhood they already have implicit bias against and worse, they believe someone is armed, that situation is not going to end well.”

Ethan Dodge, Citizens Privacy Coalition of Santa Clara County

Police said the cameras and systems should not impede on citizen’s privacy because they are only placed in areas where “citizens have no legal expectation of privacy,” like street intersections or crosswalks.

The Police Department also noted that the detection systems are mounted on power poles in plain sight and not hidden from the public.

However, police said the video captured could be used in other crimes, regardless of whether a gun is shot or not. All video evidence collected would be held for a year by San Jose Police, pursuant to the city of San Jose retention policy.

To Dodge, however, “a technology can have perfect privacy (policy) and still cause a lot of harm if in the wrong hands.”

The pilot program will run for six months with no cost to the city. If the city likes the program after the six-month period, it may be expanded to other parts of the city.

The gunshot detection system has been used in other California cities like Oakland, Sacramento, San Diego, Bakersfield and Salinas.