Patent ID: 7618010
Filing Date: 2009-11-17
Classification: B61L

Abstract:
1. In a railroad crossing warning system having an electronic transmitter located on a first side of a road crossing connected across both railway rails, a first electronic receiver on the first side of the road crossing connected across both railway rails, a second electronic receiver on the second side of the road crossing connected across both railway rails, a method for determining direction a vehicle is traveling, the method comprising: monitoring a voltage profile from at least one of the first receiver and the second receiver, as a vehicle moves along the railway rails towards the road crossing; and determining a direction the vehicle is moving based on the voltage profile; comparing a first voltage curve of the first receiver to a second voltage curve of the second receiver, wherein comparing is performed relative to at least a first and a second relationship of the curves, each expected relationship associated with a different direction of vehicle travel; and determining a direction of travel of the vehicle based on comparing the first voltage curve of the first receiver to the second voltage curve of the second receiver.