Do you read what I post or just react to it

I did not say that my lights were pointed high. I said that my helmet light is mounted higher than my bar lights. Pretty self explanatory. Of course it would be mounted higher than my handlebar light because it's mounted on my head! As to where it is aimed, it is aimed downward a few feet further down the road than the handlebar light. That puts the central part of the beam at about 2 car lengths in front of the bike...about 30 feet. I don't wear the helmet light for fashion...I use it for function. If the light is "pointed high", it's of no use and why would I even want to carry it?

You know nothing...nothing...about me or how I use my lights. I am extremely considerate of other road users. I am also very cognizant of where my lights are going and what they are doing. That is why I have said you are completely wrong about blinding other road users (at least the ones who are riding or driving the right way on the road) with bicycle lights that are separated by 10 to 15 feet from motorists and 20 to 25 feet from other bicyclists.

I agree that you about shadows having an effect on depth perception. I just happen to disagree that long shadows, i.e. those cast by low mounted lights...notice that "mounted" word again..., improve depth perception. I've ridden with lights mounted on the fork blades, at the headset, at the bars and on the helmet. Of those 4 places, mounted on the blades is the absolute worst place to mount a light. Tiny pebbles cast shadows that are inches long. Each of those long shadows are places where wheel trapping stuff can hide. Mounted at the headset, the shadows cast by the light are shorter but still long enough to hide road hazards. Bar mounted lights cast shorter shadows that hide less stuff and illuminate the road better. Helmet mounted lights cast the shortest shadows of all. Short shadows give far better depth perception than do long ones.

No one here has ever said that they shine their helmet light in the eyes of on-coming traffic. That would, indeed, be stupid...even given that the light is a long distance away and the output attenuated by beam spread. If we have to flash out helmet lights in across someone's hood, it is momentary and is used in the case of a motorist not seeing a bicyclist. In that case, the motorist is endangering the life of the bicyclist and the flash is meant as a warning. The most often time I have had to use this technique is when the motorist is stopped at a cross street and is pulling out without seeing me. Should I just let them hit me? Don't want to blind the poor person, why don't I just lie down here and let them crush the life out of me? That way they won't be blinded, pull away from the stop sign, speed down the road, and kill you on a blind corner?

Jeez, Robert, it's not like bicyclists with helmet mounted lights are walking up to motorists and shining 300 or 400 or 1500 lumens in their eyes from 3 inches away That would be inconsiderate. We are flashing a little bit of light at them for a moment...far less than a second...from many feet away (20 or 30 or more). Even you, light expert that you say you are, should know something about light density. You even set up a test rig and measured what the lux is for the Magicshine. What is the lux (lumens/sq meter) at 2 feet, 5 feet, 10 feet, 20 feet, 30 feet, 50 feet?

My halogen lamp has an output of 1500 lumens. At 10 meters and a 12 degree reflector, the beam is almost 6 meters wide. That's 28 sq meters of area. The light spread over that area evenly (my beam is very even from edge to edge), gives 54 lumens per meter. A human face takes up way less than 1 meter in area but even if I were to hit a person full in the face with 54 lumens, that's still not much light. Certainly not 'blinding' or enough for them to go careening off the road.

And the driver that is coming at them is going to spray far more light into their eyes than I can because their 1500 lumen light is much closer and, thus, has a higher lumen density.