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San José Adding Hundreds of License Plate Readers Amid Privacy and Efficacy Concerns

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A man with a fluorescent yellow coat holds a black machine.
A Flock Safety worker holds up a new Automated License Plate Reader that was being installed in East San José on Tuesday, April 23, 2024. (Joseph Geha/KQED)

In an effort to address crime, San José is rapidly blanketing the city with hundreds of automated license plate readers.

Mayor Matt Mahan helped install the city’s 235th device this week and said San José aims to have 500 up and running by the summer. Leaders say the ALPRs from Atlanta-based Flock Safety are a critical support for investigators.

“It has already proven an incredible tool for our thinly staffed police department,” Mahan said Tuesday during a press conference in East San José where a new ALPR was being installed.

He said the network of cameras in 2023 alone helped recover $2 million worth of stolen vehicles and led to the arrests of nearly 200 people suspected of crimes.

Acting Police Chief Paul Joseph said the ALPRs have been invaluable.


“These cameras make a difference by helping to identify and apprehend suspects, curbing criminal activity and providing crime victims with a feeling of closure and justice,” Joseph said.

However, some privacy advocates and residents say the cameras aren’t actually effective at reducing crime and instead create massive logs about the movements of locals and visitors. They worry about the amount of data police are keeping, the length of time it’s retained, and how it is shared across law enforcement agencies.

“Complicated issues like safety deserve really well thought out and focused solutions,” said Nick Hidalgo, a staff attorney for the American Civil Liberties Union of Northern California.

“Installing hundreds of expensive devices that effectively turn San José into a surveillance city is like using a bazooka instead of a fly swatter. It’s expensive, unnecessary, ineffective and does a lot more harm than good.”

The Flock devices capture not only license plates but also a car’s make and model and other characteristics like customizations or bumper stickers. Flock’s software pings police when a car matching a “hotlist” crosses the path of the cameras, and police can also search the data logs for specific cars and plates.

Officials say the cameras do not have facial recognition features, nor do they photograph inside a car. City officials said they are proud of the data privacy protections San José follows and noted that the data, under state law requirements, is only shared with other California law enforcement agencies and is prohibited from being used for immigration enforcement.

Danny Garza, a 65-year resident of East San José’s Plata Arroyo neighborhood, trusted the police to handle the information securely and said he and others have requested cameras be put up in the area for years.

“We’re asking that these license plate readers help protect layer upon layer of community gains,” Garza said. “All we’re interested in is community safety. We’ve had shootings in the past, and they’ve gotten away. Nobody knows where they went.”

Though police leaders say the technology is effective and has helped capture people suspected of car theft, rape, and homicide, among other crimes, the department declined to use a specific metric to measure the success of the program over time.

A white middle aged man speaks into microphones wearing a blue suit and a white collared shirt with no tie.
San José Mayor Matt Mahan during a press conference in East San José where a new ALPR was being installed on Tuesday, April 23, 2024. (Joseph Geha/KQED)

“We like to measure our success in terms of usefulness in our pursuit of public safety by solving and reducing crime,” Sgt. Jorge Garibay, a department spokesperson, told KQED in an email.

“Crime trends fluctuate, as do crime types. What most of these have in common is a mode of transportation to and from the scene of crime. When that mode is a vehicle, ALPR success is achieved when a hit has been broadcasted and officers have a tangible lead to follow up on.”

The cameras installed to date — 241 of them as of this writing — are already amassing huge troves of data about the cars driving in San José. The current camera network has detected nearly 3 million unique cars per month, according to the city’s Flock portal.

In just an 18-day period in December 2022, the city’s cameras captured nearly 16 million total scans, which can include multiple scans of the same vehicle in different locations, according to police. The total scans will only increase as the city’s arsenal of cameras more than doubles.

“It casts a net over the entire community, tracking where drivers go and allowing law enforcement to, if they chose, create maps of where drivers work, live, worship, seek medical care, and travel,” said Hidalgo of ACLU Northern California.

His research into San José’s ALPR program from 2022 showed that more than 99.99% of the plates scanned do not match any hotlists for police. If the car or plate is not implicated in an investigation, the SJPD then keeps every plate scanned for a year before purging it.

Many law enforcement agencies using similar Flock systems purge license plate data every 30 days.

Hidalgo said it’s not just invasive that police track that much data on people who aren’t suspected of any crimes, but by keeping it for a year, the city puts the data at further risk for misuse or to be inadvertently disclosed in a data breach.

Joseph, the police chief, said the department keeps the data for one year based on the recommendation of the city attorney’s office, indicating the law requires it.

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Albert Gehami, San José’s privacy officer, said the city is aware other agencies do not keep similar data for as long as San José does.

“When it has nothing to do with an investigation, a year is excessive,” Gehami said of the data. “Police departments up and down, everyone that we speak to, [say] there is no need for that information. It is strictly what our attorney’s office has decided is the current interpretation.”

City Attorney Nora Frimann said the retention period has been in place for more than a decade, going back to when the police department trialed other license plate reader technology and before the state required cities to have formal ALPR policies in place.

“It just made sense to keep it for a year,” Frimann said. However, she noted the retention time is a policy question that the city council can change if it sees fit. “As a city, we can revisit the time frame,” she said.

The extra time San José police choose to keep the data also costs the city more money.

San José police could not immediately provide total cost estimates for the program but noted that each camera costs the city about $2,500 per year to lease from Flock, along with a $350 one-time fee.

Flock’s head of policy and communication, Josh Thomas, said San José pays an extra $300 per camera each year for the longer data retention periods.


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