Merely anecdote: I ride each weekday morning/evening, year long, and I have been hit 4 times by automobiles -- All in the evening, and all during sunlight hours. I have never been hit at night. I wear brightly colored, reflective clothing at all times (daylight/darkness). I also use 2 headlamps, 2 rear lights and 3 rear reflectors.

I am guessing that the lights make me more visible during darkness than bright clothing during daylight, therefore I don't get hit. But it's just a guess.