Well, all I know is that I want to be seen from the back. If it irritates someone riding with me or the car behind me, I'm a happy guy. However, when I put the brakes on, I want it to be much brighter than the running lights.
With that being said, on my Ultra there just isn't much area to place additional lights etc.. (I've got a Ugly leather tour pack) I installed the HD LED tail light which does help. Key word, tail light. (singular) So, for night, I got some of the black reflective tap that looks white at night in the lights and installed on the back saddle bags. Good for night, but invisible during the day which doesn't help much during the day. Anyone that has a good idea for lights for day use, let me know. (The dual lighting system on the 07 Ultra seems to have some issue is reason I don't install the module) Ok, just my 2 cents worth. Have a good day.
Ugly John