lights & hi-viz make it easier for attentive road-users (motorists, bicyclists, pedestrians) to see you sooner and from farther away, but if someone is inattentive (texting, watching a movie, eating breakfast, etc) then it won't make a difference. as noted, people crash into stopped emergency vehicles with lights blazing.

the problem isn't bicyclists' lack of lighting & hi-viz... the problem is inattentive road-users (motorists, bicyclists, pedestrians). it doesn't help that the legal system too often interprets "i didn't see him" as a get-out-of-jail card, rather than an admission of careless driving, or worse.