Visual Aiming of Low-Beam Headlamps: Effects of Experience and Ambient Light

摘要

Recently there has been a considerable amount of interest in formally adoptingvisual aiming for headlamps in the United States. Because of this interest, several studies have been made of how the sharpness of the cutoff affects the accuracy with which a low-beam headlamp can be vertically aimed. However, a number of issues have not been resolved. The present study was undertaken to address two of these issues: (1) how background light on the aiming screen affects visual aiming, and (2) whether the training and experience of the persons doing the aiming affect aiming performance. Two experiments on visual aiming were conducted. The results demonstrate clear effects of ambient illumination of the aiming screen on the mean position set by visual aiming, but provide no evidence for an effect on variability of visual aiming up to the maximum level examined, 108 lux. The effects on mean aim, although highly significant statistically, are not large relative to estimates of the current variability of headlamp vertical aim in the United States.