Originally Posted by FBinNY

As you look at the Lincoln Tunnel video, notice how much better the lights stood out in the dark, while both the bikes and the lights faded and blended with the low level ambient light of the tunnel.

The lowest visibility isn't in the dark, it's in twilight. This time of year it's full dark when I ride home from work. But a month ago, I either got out early enough while it was still bright, or killed 1/2 an hour waiting for it to get darker. This is based on years of experience, and light checks of my own bike and lighting at various ambient light levels.