Evolution of a U.S.-ECE Improved Headlamp Beam

Conventional U.S. and European headlamps were used as a basis for comparison with three experimental mid beams in field tests to evaluate visibility and glare of alternative “meeting” beams. Mean visibility distances of targets to the left of the drivers, at the center line of the two lane road used, were about half of those for the targets at the right side of the lane. Visibility distance of targets at the left of the lane were slightly greater with the ECE low and the mid beam using the ECE low beam than the other beams, but only close to the meeting point. Mean visibility of targets on the right of the lane was up to 24% greater with mid beams than either U.S. or ECE low beams. Discomfort glare was rated the same for all beams for targets on the right; but less for the ECE low beam and the mid beam using the ECE low beam than the mid beams using the U.S. low beam when observing targets on the left. It was concluded that improved meeting beams should use headlamps similar to the ECE low beam for urban driving, augmented by a third lamp such as the U.S. “type III” lamps used in these tests to form the “ECE-US mid beam” for use as a meeting beam on two lane and divided highways.