2 years ago, Driving Vision News published a report focused to the influence of aiming on glare and visibility. Below are the main conclusions:
1) Influence of vertical aiming on glare
– Xenon headlamp misaimed upward 0.5°D produces unacceptable glare of 5 lux which again is 5 times the nominal maximum in the technical regulations and ranks as close “Disturbing” on the De Boer scale with a rating of 3.5.
– Xenon headlamp misaimed Upward 1°D produces catastrophically high levels of glare, more than 20 lux which is 20 times the maximum permissible level.
It ranks at a level between “Disturbing” and “Unbearable” at the De Boer scale with a rank close to 2.
Conclusion on Influence of vertical aiming on glare
1. A vertical misaim of 0.5°D up is unacceptable with worsening De Boer scale by 1.5.
2. Glare increases by a factor of 5 with lamp upward 0.5°D misaimed and by a factor of 20 with lamp upward misaimed 1°D.
The vertical aim tolerance for adequate headlamp glare control should be: -0.57°D +/- 0.25°D
2) Influence of vertical aiming on visibility gradually increases with upward misaiming.
Visibility illumination is reduced by a factor of 5 if misaimed 0.5°D.
Visibility illumination is severely degraded by a factor of 25 to well below the minimum acceptable level, if the headlamp is misaimed 1°D.
Only a Downward misaimed of 0.5°D is permissible even the great decrease of visibility