I ride to the Wednesday night rides. Sometimes on a bike path that is totally straight to the shop where riders are waiting and just standing around. About a mile away if there is one rider with the new safety green/yellow solid jacket. I can see the bright color with my sunglasses in sunlight. I can't tell what it is from a half mile to a half mile but I can see it. Sometimes when I get there, there are 5-10 riders standing around Can't see well enough to see they are cyclists there until I get closer.
My Cygolight pro 200 hotshot taillight is much brighter than most car taillights. In the daytime it is almost blinding from a block away and easy to see from a few blocks in sunlight. Same for my tiny Cygolight "dice" white front flasher.
When ever I get a new light I walk way away from it to see the visibility it has. I also move right to left to see what the side spread is like. I do it in daylight and the dark, with ambient light and in total darkness.
I'm surprised that some riders apparently don't do this. Do others do it? ??