One of the basic rules of bicycling for all California bicyclists is to wear a helmet. It is important to wear a bicycle helmet while riding, because in the event of an accident, the helmet may be the only thing standing between you and almost certain fatal or catastrophic brain injury.
The right kind of bicycle helmet is one that fits you comfortably. It goes without saying that if you're not comfortable wearing a bicycle helmet, you're much less likely to wear it, and that simply increases your risk of suffering a serious brain injury during an accident.
The helmet must not be too snug or too loose. It should not be so snug that it pinches, or bothers you while riding. On the other hand, the helmet should not be too big for your head. A helmet that's too big will still fail to protect your head in the event of an accident, because the head will be able to move around inside the helmet.
One of the biggest mistakes that bicyclists make when they buy a helmet is to buy one without bothering to try it for size. Helmets can differ based on the size of the inside of the helmet, and different manufacturers have different sizes. It is absolutely essential that you try on a helmet for size before you buy it. When you try the helmet, make sure that you fix the straps.
However, wearing a helmet doesn’t guarantee protection against injuries in a bicycle accident. Most helmets will only protect your head during a fall from your bicycle at fairly low speeds, and will do nothing to help protect your head in a typical accident that involves a high-speed motor vehicle crash.