Abstract: A computerized ultrasonic system is disclosed for classification of vehicular traffic, as at a toll collection booth. An ultrasonic ranging unit is mounted above the traffic lane, facing downward. The unit is activated by the presence of a vehicle and proceeds to measure repetitively the momentary vertical distance of the vehicle from the ranging unit. Processing circuitry is provided to ascertain average and maximum height, rejecting aberrational readings, such as from an antenna. The computerized system may include a "look-up" of standard vehicular categories, enabling classification of vehicles by comparison of the data received with pre-programmed standard categories.