Law enforcement agencies love their automatic license plate readers. ALPRs do what cops physically can’t: scan millions of plates a year and run them against a number of shared databases. The systems are black boxes. The public is often given little information about how many plate images databases store or for how long. Law enforcement agencies rarely audit the data, providing zero insight on the number of false positives ALPRs return. Non-hit photos are sometimes held indefinitely, creating databases of people’s movements.
All of these negatives are supposed to be outweighed by the fact that cops sometimes catch criminals with ALPRs. How often this happens is anyone’s guess. Officials will tout the tech’s ability to track down criminals, but these anecdotes are usually only provided when government officials start asking questionsabout the tech — questions they should have asked during the approval process.
Getting tagged as a hit by an ALPR is a frightening experience for innocent drivers. The tech tells cops they have a potentially dangerous criminal on their hands and they react accordingly. Drivers are somehow supposed to prove a negative at gunpoint and their inability to do only ratchets up the tension.
A false hit by an ALPR has resulted in a federal lawsuit [PDF]. And the Contra Costa (CA) Sheriff’s Department quite possibly found the worst person to pull over because a machine told it to.
As chair of Oakland’s Privacy Advisory Commission, [Brian] Hofer, 41, has railed against what he describes as the seemingly arbitrary use of Automated License Plate Readers — cameras that ping police and private agencies by matching plate numbers with “vehicles of interest.”
So the irony is not lost on him when he said he and his brother, a 23-year-old political science student at UC Berkeley, were detained, sometimes at gunpoint, on Nov. 25 when a license plate reader near the San Pablo Lytton Casino off Interstate Highway 80 alerted police that they were riding in a stolen car.
Out came the guns, attached to officers sure they had caught a car thief. Hofer and his brother were detained at gunpoint while their rental vehicle was searched. Nearly a half-hour passed before any deputy attempted to determine whether the rental vehicle/contract was legit. Compounded errors are always a potential problem, but they reach critical mass quickly when government power attached to deadly force is involved. Here’s the backstory to the stop — a string of system failures that could have resulted in injury or death.
Turns out though, that while the rental car he was driving had indeed been stolen from San Jose in October, either the police or the rental car agency hadn’t updated the proper authorities that the white Getaround Kia had been recovered and should therefore be removed from the “hot list” database.
The question isn’t necessarily whether or not officers responded to the hot list hit inappropriately. The question is whether this response — which has the potential to see people not only wrongfully detained, but possibly injured or killed — is worth the tradeoff. Law enforcement will always say the errors are worth the labor tradeoff when it comes to ALPRs. Citizens held at gunpoint and warrantlessly searched will always disagree with this assessment.
It’s up to those policing the police — city/county/federal authorities — to make the right call when it comes to ALPRs. Without better data on these devices’ potential for error, government officials are literally trading citizens’ live and liberty for law enforcement convenience.