If the light is intense enough that drivers tend to looking away, then they aren't seeing ME in a useful way. (The same thing that happens when an oncoming car's headlights are too intense - other drivers become unable to see a large part of the whole road ahead of them.) My beam is much more concentrated than a car's tail-light, I think. The fact that people are hanging on my tail at 10MPH when they could easily pass seems to indicate a possible problem, besides being a bit nerve-wracking. I really worry about the guys behind the first one who've been shielded from seeing me until the last moment when they finally pass. My night route is up rolling hills, so the up-down angle of the light to the observer varies a bit with their distance, which makes it hard to optimize. I might try changing the direction of the beam side-to-side a bit, though. The problem is monster trucks with over-wide tires are all the rage here, and these kids can hardly keep their big rigs on the road sometimes. Those are the guys I don't want zooming by, and I have to tip the light up farther for them than for a car, so the poor people in sensible cars are getting screwed yet again. I was surprised by the intensity of the beam in the dark, though. That oval beam lens works really well for a tail-light.