During a breakfast run yesterday, with a group of 5, I was near the rear on the trip out to the restaurant. The lead rider happened to mention to me later that he could see every ones headlights, in his rear view mirror, except mine. He asked if I ran with my lights on dim or bright? Never had given this much thought before and always ran them on dim (during the day). He advised running lights on bright all the time. Curious what others do with their lights while running in the daytime?