PS-- It also needs to be said. I have never seen anyone mention the fact that your lights need to be bright enough to show you what is happening in front of you, when you are blinded by the lights of oncoming drivers. When even the low beams of oncoming traffic shuts your pupils down to pinpoints you need serious lumens coming out of your own lighting to keep you safe. I know I need more light at night than other people but, I don't seem to have trouble getting the amount of light I need from car headlights. Nor does anyone need to spend $1k+ on automobile lighting to get adequate performance nor, conversely do they have to stumble around with sub-optimal amounts of lights because that is all they can afford. Interesting that the DOT classifies bikes as legal road vehicles subject to all the responsibilities of road usage that such a designation mandates but then stipulates only that a rider have lighting that allows them to be seen. Once that low bar is achieved you are free to go out there in the dark with as little light as you think you can get away with.