Originally Posted by
JohnJ80
Exactly right.
One does not aim one's beam straight out into space at driver eye level. To be effective, you aim the beam at a slight downward angle. Gets really tough to blind anyone when you do that AND the light isn't useful many other ways.
J.
Actually when aimed like you describe about 40% of the light output from typical conical optics will be above the horizon and in the eyes of oncoming traffic. Further it produce a center oval shaped bright spot on the road in front of you. Typically that bright oval is much brighter than the surrounding light which makes it more difficult for the cyclist to see in the less well lit areas. That is why the German specs encourage dyno lights to have more uniform (and gradated) lighting patterns.