This morning on the ride in I saw a young lady commuter on a black mtn bike, wearing black lycra shorts, and a black sleeveless jersey, with a black backpack. When she passed under some of the overhanging oaks and was in the shadows, I could hardly make her out when I was 50 feet behind her.
I pulled up beside her, and after a few pleasantries mentioned that it was hard to see her and suggested she wear something a little brighter. I'm not sure if she heard everything I said because of occasional traffic noise.
One of the things we emphasize in our Effective Cycling (Bike Ed) classes is being visible, day and night. I hope she got the message.