The cops can look up your driver license info with your birth date and address. I was just pulled over recently without my license and they did just that. Fortunately that was enough to convince them I had a valid driver's license and they didn't require a picture id to confirm my identity. I guess you could conceivably use someone else's birthday and address to get out of a ticket. That'd be pretty f-ed up though.
Anyway, probably the cops looked up his info and then confirmed his identity with the photo from google images. That is all.