noglider: In 2016 I was hit by an inattentive driver less than a mile from my house. I live in a rural area with little traffic. I had noticed that close passes had been increasing and had given it not much attention up to that point. After being sideswiped I was focused on how to prevent another situation like that. I had heard of daylight viability lights so I looked on the web. I saw the Dinotte lights and picked out there daylight only one. They have you check a box that states you will only use it in daylight. It is so bright that a close up look see behind the bicycle is uncomfortable to my eyes. When riding in traffic I can see cars in my mirror move to the left from quite a distance back. If your light has no visible effect to you on how traffic responds then I would find one that does. I also run a generator light set that is good for at night.