A little subtle, but one additional problem is that the vehicle is being matched to a ticket by the plate number's string. The result is that old tickets are be

A little subtle, but one additional problem is that the vehicle is being matched to a ticket by the plate number's string. The result is that old tickets are being keyed to whoever currently has that plate number. A proper system would lookup that vehicle's registration_id at the time of the violation and store that as the foreign key.