Good ideas, folks. Now I'm thinking about adding reflectivity to clothing. I was able to wrap yellow reflective tape around my pedals, and I suspect it's as good as pedal reflectors.

I once used iron-on reflective tape on the backs of my gloves, and I made arrows out of it hoping it would be a kind of turn signal. I have no idea how visible it was. I think I should do it again since of course my gloves are black.