and lots of idiots take them off for no reason at all. Retroreflective gear isn't the be-all end-all in safety equipment, but it sure helps. I always add reflectors and reflective tape to every bike that passes through my hands, so the bike does the work and I don't have to wear a dorky hi-vis kit jacket. reflectors on pedals and cranks are in motion when you are pedaling and work as well as a rear blinkie for visibility to following motorists at night, without batteries; test it sometime on the road with car headlights and you will see.