Abstract: An improved traffic monitoring system is disclosed in which a microprocessor is connected to an analog to digital converter providing a series of digital samples of the pressure within a road tube for analysis of the signals. If a pulse is detected exceeding a threshold level, corresponding to passage of a tire over the road tube at a relatively high rate, the microprocessor then determines whether pressure in the tube subsequently drops below a repetitively-updated baseline value. If the pulse in the pressure does not exceed a predetermined threshold, the microprocessor determines whether the pressure continues to rise for a stated period of time and to exceed a set minimum value, whereupon the conclusion is reached that a relatively slowly moving tire has passed over the road tube. The microprocessor is disabled from detecting a second tire within varying intervals after detection of a pulse.