The Human Toll of ALPR Errors

This post was written by Gowri Nayar, an EFF legal intern.

Imagine driving to get your nails done with your family and all of a sudden, you are pulled over by police officers for allegedly driving a stolen car. You are dragged out of the car and detained at gun point. So are your daughter, sister, and nieces. The police handcuff your family, even the children, and force everyone to lie face-down on the pavement, before eventually realizing that they made a mistake. This happened to Brittney Gilliam and her family on a warm Sunday in Aurora, Colorado, in August 2020.

And the error? The police officers who pulled them over were relying on information generated by automated license plate readers (ALPRs). These are high-speed, computer-controlled camera systems that automatically capture all license plate numbers that come into view, upload them to a central server, and compare them to a “hot list” of vehicles sought by police. The ALPR system told the police that Gilliam’s car had the same license plate number as a stolen vehicle. But the stolen vehicle was a motorcycle with Montana plates, while Gilliam’s vehicle was an SUV with Colorado plates.

Likewise, Denise Green had a frightening encounter with San Francisco police officers late one night in March of 2009. She had just dropped her sister off at a BART train station, when officers pulled her over because their ALPR indicated that she was driving a stolen vehicle. Multiple officers ordered her to exit her vehicle, at gun point, and kneel on the ground as she was handcuffed. It wasn’t until roughly 20 minutes later that the officers realized they had made an error and let her go.

Turns out that the ALPR had misread a ‘3’ as a ‘7’ on Green’s license plate. But what is even more egregious is that none of the officers bothered to double-check the ALPR tip before acting on it.

In both of these dangerous episodes, the motorists were Black.  ALPR technology can exacerbate our already discriminatory policing system, among other reasons because too many police officers react recklessly to information provided by these readers.

Wrongful detentions like these happen all over the country. In Atherton, California, police officers pulled over Jason Burkleo on his way to work, on suspicion of driving a stolen vehicle. They ordered him at gun point to lie on his stomach to be handcuffed, only to later realize that their license plate reader had misread an ‘H’ for an ‘M’. In Espanola, New Mexico, law enforcement officials detained Jaclynn Gonzales at gun point and placed her 12 year-old sister in the back of a patrol vehicle, before discovering that the reader had mistaken a ‘2’ for a ‘7’ on their license plates. One study found that ALPRs misread the state of 1-in-10 plates (not counting other reading errors).

Other wrongful stops result from police being negligent in maintaining ALPR databases. Contra Costa sheriff’s deputies detained Brian Hofer and his brother on Thanksgiving day in 2019, after an ALPR indicated his car was stolen. But the car had already been recovered. Police had failed to update the ALPR database to take this car off the “hot list” of stolen vehicles for officers to recover.

Police over-reliance on ALPR systems is also a problem. Detroit police knew that the vehicle used in a shooting was a Dodge Charger. Officers then used ALPR cameras to find the license plate numbers of all Dodge Chargers in the area around the time. One such car, observed fully two miles away from the shooting, was owned by Isoke Robinson.  Police arrived at her house and handcuffed her, placed her 2-year old son in the back of their patrol car, and impounded her car for three weeks. None of the officers even bothered to check her car’s fog lights, though the vehicle used for the  shooting had a missing fog light.

Officers have also abused ALPR databases to obtain information fo