Patent ID: 6278380
Filing Date: 2001-08-21
Classification: G08G

Abstract:
A method of sensing a vehicle, comprising the steps of:placing first and second loop coils at respective positions separate from each other by a predetermined distance;generating a first electric signal depending on an inductance of the first loop coil;generating a second electric signal depending on an inductance of the second loop coil;detecting a speed of a vehicle, which passes through first and second given regions determined by the respective positions of the first and second loop coils, in response to the first and second electric signals;comparing the first electric signal with a reference signal to decide whether or not a vehicle passes through the first given region determined by the position of the first loop coil;controlling the reference signal in response to conditions of the first electric signal which occur in a follow-up time; andchanging the follow-up time in response to the detected vehicle speed.