Patent US 5,929,784

A device for determining the distance between vehicles according to this invention is used with a vehicle for determining the distance to a vehicle ahead of the device-equipped vehicle moving on a traffic lane defined by lines drawn on a road. The device comprises a pair of light receivers each having at least one light sensor array, a line detector for detecting images at points at which the quantity of light takes maximum values on the light sensor array of at least one of the light receivers as the lines and providing an output signal representing the positions of the lines, a measuring range detector responsive to the output signal of the line detector for detecting a range of the traffic lane on which the device-equipped vehicle is moving; and a distance detector for determining the distance to the vehicle ahead on the basis of positions where an image of the vehicle ahead is formed on the light sensor array within the range of the traffic lane detected by the measuring range detector.