While I do fine with a medium bright headlight, I think a searing bright rear light is a must. Here's my thinking: You are on a two lane 55mph road with a car coming at you and one coming up behind. The oncoming car either fails to, or does not dim it's brights. Both me and the driver coming up behind are blinded. I want the car coming up behind me to see my taillight and know I'm there. I won't use anything dimmer than a Dinotte taillight if I'm going to be on a high speed road.