Recently, Sen. Carol Liu introduced a bill requiring adults to wear helmets while riding a bike in California. If your caught without a helmet the base fine would be $25. The bill can be voted on as early as April. In California it's already illegal to ride a bike without a helmet if you're under 18.
Bicycle groups in California have been massively negative about this safety proposal with some strange reasoning. Some groups claim that the law makes bicycling seem dangerous and others fear it will hurt ride shares over helmets. Both arguments have little fight in them as it has been proven to be dangerous to ride bicycles in LA and California abroad with the multiple stores of accidents, many that could have had riders less hurt if only they were wearing a helmet. The ride share argument makes little sense, you couldn't get adjustable helmet with those bikes or bring a helmet in your bag or backpack if using the program?
We have young adults as old as 17 ride with helmets? Why would we stop enforcing the law when your older. Does your skull magically grow thicker to save it from smashing into asphalt?