Motorcycle headlighting : experimental and computer simulation comparisons of nighttime visibility distances obtained with various headlamp beams.

The distances at which a target could be identified at night by five motorcyclists were measured using various headlamp beams. A typical Japanese symmetrical low beam (a-9200), a European asymmetrical low beam (h-1), a u.s. asymmetrical low beam (4458), and two high beams (a-9200, 4458) were used to identify a target positioned either at the right or left of the test lane. The results were compared with predictions of identification distances made by a computer simulation program. Of the low beams, those with an asymmetrical beam pattern provided overall superior performance, having visibility on the left at least equivalent to the symmetrical low beam and substantially greater visibility on the right. The h-1 beam had the best visibility to the right and left. The high beam headlamps provided the greatest visibility distances, with the a-9200 beam giving somewhat less visibility to the left than to the right, and the 4458 beam having equal right and left visibility distances. The simulation program closely predicted the low beam visibility distances, but overestimated those obtained with the high beams. For the covering abstract of the conference see IRRD 268805.