The RIF says that these tests demonstrate that while this face recognition tool has “improved,” it isn’t always able to get photos of every vehicle passenger, especially if they’re in the second or third row. “Human behavior, multiple passenger vehicle rows, and environmental obstacles all present challenges unique to the vehicle environment,” the document says. The current iteration of the system matches a person’s photo to their travel documents in what’s known as one-to-one face recognition. This differs from one-to-many face recognition, which police may use to identify a suspect based on a surveillance photo, where the primary risk is someone getting a false positive match and being falsely identified as a suspect. Maass says it’s unclear whether CBP’s error rates primarily have to do with the cameras or the matching system itself.