Automatic License Plate Readers: Rental Cars and Fourth Amendment Privacy

In the 2018 Carpenter decision, the U.S. Supreme Court held that the Fourth Amendment right to privacy includes a right in the “whole of their physical movements.” The Carpenter case involved searches of historical cell data, but with the number of cameras recording passing cars, it was only a matter of time before law enforcement searched databases of license plate readers. However, is your right to privacy violated merely because the government was able to find you through a car in a database or do you have to legitimately own or rent that car? In other words, if someone doesn’t return a rental car on time, is their right to privacy violated when the police use a license plate reader to track you in the rental car even though they don’t have a right to use the car?

In U.S. v. Yang¸ the Ninth Circuit had a chance to tackle this issue but ultimately punted. The defendant allegedly committed a crime while driving a rental car which he then failed to return timely. Investigators then went to an automatic license plate reader (ALPR) database called LEARN, which is only available to law enforcement. This database is accumulated from both commercial vehicle cameras and from cameras on law enforcement vehicles.

By searching the ALPR database, investigators found a hit at a certain intersection and found the rental car nearby. The defendant then argued that the search violated his Fourth Amendment right as recognized by the Carpenter decision. This issue was appealed to the Ninth Circuit Court of Appeals, which held the defendant did not establish a reasonable expectation of privacy in the historical information of the rental car. There was no evidence the rental car company had a policy or practice of allowing renters to keep their cars beyond the rental return date, and the rental car company had in fact taken action to recover the vehicle.

The Ninth Circuit Court’s decision is interesting because it is still unclear how Carpenter is going to be applied in the digital age. The court’s reasoning suggests that you have to have a legitimate privacy interest in the car, but ultimately, that did not matter as the defendant had no reasonable expectation of privacy. However, the court did not resolve whether the timing of the search mattered. If you had a legitimate interest in the car when your license plate was scanned but not when the ALPR database is searched, were your rights still violated? The world’s servers are filling with historical location data, so this will continue to be an evolving area of the law for some time to come.