just the fact that this question even exists gives me hope that I'm not the only one with a helmet fetish. Helmet fetish seems to be a bit rare, I have never heard of any other ones until a year ago...
Being extra careful and attentive to the surrounding is the key precaution to take to prevent bike crashes. Look out for yourself as well as for other cars to prevent serious injuries.
Crash helmets reduce injuries by absorbing most of the impact shock. An easy to understand example is how an egg carton made of foam keeps the fragile egg from cracking by taking all of the knocks...