I am going to add a proviso: Cycling helmets can provide protection if you should have a fall, but they are not "bulletproof" . I have been using a cycling helmet for a half century. I don't regard it as a protective device, but only as a last chance if I don't ride as carefully as possible. Over those last 50 years there were a couple of times when I might have whacked my head on something during a fall, but nothing that might have been life changing. Helmets help, but nothing can substitute for riding carefully
This is from someone who did bike races for 20 years