Originally Posted by
Moe Zhoost
...Bike lighting is especially tough because of the narrow separation between lights. This makes it hard for drivers to gauge closing speed. Two average lights at at least 15" apart will be much better than a single super light...
Valid point. I was thinking about how some motorcycles have rear lights with some separation, which helps drivers estimate size, approach speed, etc.
The widest points on my bike would be the rear rack supports -- only 6" to 8" -- and handlebar ends (24" at least) -- but perhaps enough to help lend some sense of proportion.