Currently, FasTrak transponders are not compatible with E-ZPass and other ETC systems used in other states because they use a different specification than Title 21. If a vehicle does not have a transponder, or if a transponder is not detected at the toll plaza, a violation enforcement system triggers cameras that capture photos of the vehicle and its license plate for processing. If the license plate is registered as belonging to a FasTrak user, the account is debited only the toll charge, and no penalty is charged. This is a backup in case a transponder fails to read. Otherwise, a toll violation notice is sent to the registered owner of the vehicle. In the case of drivers whose vehicles are company owned or leased, as long as the vehicle license plates are properly listed, the violations will be sent to the registered owner and not the employee driver. It is for this reason that the License Agreement mandates that customers list all vehicles, including motorcycles, motor homes, and trailers of all types on their accounts so that when transponders fail to read the toll can be debited based upon the vehicle's license plate. A license plate may be listed only on one account.