On a dark country road, I sometimes only use 80 Lumens especially when noodling along at 12.7 mph. Rounded a corner on an evening ride once and seemingly out of nowhere there was a train crossing light. It was really blinding. It seems like it took 20 minutes before my eyes adjusted to the dark. I know we all differ in our night vision. My son can see deer across the cornfield when it is dark and I need good german glass to faintly make the silhouettes out. His eyes also adjust back to good night vision quicker. I almost wonder if putting out too much bike light on dark country roads limits some aspects of vision (peripheral and distance).....are we blinded by the bright LED lights. Can they be too bright or too white. I suppose I should read up...sorry.