Bicyclists in California can decide to wear a helmet or not when riding.
Although, wearing a bicycle helmet is something you should do whenever
you ride on public roads.
The two benefits of bicycle helmet use are:
It helps prevent a brain and head injury if you get into a bicycle accident.
It helps keep your liability low for your own injuries.
Liability is how much you are at fault for your injuries and damages. If
you didn’t have a helmet on when you were riding your bicycle and
a driver hit you, then you can still sue them, but your chances of getting
a complete recovery will probably go down.