An apparatus recognizes road traffic lines and a car running ahead without regard to obstacles and noise signals. A video image recording unit on a car provides an image of the road ahead. Horizontal edges in the image are detected for determining the presence of a car ahead. Successive lateral sweeps in both directions from a center line that advance at predetermined sampling intervals from a proximal portion of the image toward a distal portion of the image provide data by which horizontal edges are determined for comparison against predetermined standards. A base line on the road for the car ahead is determined as the most proximal horizontal edge. Lines marking road lanes are detected by similar two directional search lines from a center line. Lane lines are identified in right and left proximal portions of the image and extrapolated to the distal portion of the image. Missing portions of lines are interpolated. In determining the presence of marked road lanes, vertical edge detection provides basic data for establishing the thickness and distance between probable lines for comparison against predetermined standards. Comparison of successive road images determines relative motion between the vehicle bearing the apparatus and detected images and aids in updating the image and eliminating noise signals.