Patent ID: 6853885

Claim:
A method for determining the speed of a vehicle passing over a roadway equipped with two coaxial, linear piezoelectric sensors, wherein the roadway defines an axis along which the vehicle passes, wherein the two sensors are parallel to each other, and wherein the method comprises the steps of: sampling signals from the two sensors responsive to passage of an axle of the vehicle over the two sensors; digitally processing the sampled signals from the two sensors to determine, responsive to the sampled signals from the two sensors, times when the passage of the axle produces each of three characteristic points corresponding to a starting point, an ending point, and a point corresponding to a maximum pressure generated by an indentation caused by the passage of the axle over each of the two sensors; and calculating from the digitally processed, sampled signals a speed value between the two sensors at each of the three characteristic points, and then calculating from the speed value between the two sensors at each of the three characteristic points a mean speed for the axle, a mean speed for the vehicle, and changes in the speed of the vehicle.