A system to detect the transit of vehicles having license plates includes at least one video camera to detect license plates capable of framing the plates of said vehicles and, preferably, at least one video camera to detect vehicles capable of framing a zone of transit of said vehicles having license plates. A series of processing operations is capable, starting from the video signals generated by the video camera to detect license plates, of detecting the presence of a vehicle in transit and, starting from the video signals generated by the video camera to detect vehicles, of detecting the position and three-dimensional shape of vehicles in transit in said zone. A supervisor module aggregates the results of these processing operations to generate records of information each identifying the modality of transit in said zone of a vehicle identified by a given license plate that has been recognized.