A system and method of registering vehicles in a road toll facility is provided with radio transmitter and receiver equipment (7) for microwaves arranged to communicate with vehicle units (12) provided in the vehicles (4), preferably including a transponder. On command from the road toll facility, an identity is obtained from the in-vehicle unit and a toll debiting operation is performed. When a vehicle (4) enters the toll facility, it is detected via the activation of the toll facility radio equipment (7) if the vehicle (4) is provided with a vehicle unit (12) and if it has performed a correct payment operation. Vehicles for which such operations cannot take place are exposed to a successive position determination via video cameras (9) through an image processing in which the vehicle in question is tracked between a predetermined recording site and the location where the payment status of the vehicle has been established via the radio equipment. In the recording site, the number plate of the vehicle is recorded for identification via a video camera (10) which identification, in conjunction with data such as time and place, is used for search and for post-debiting of the toll.