It was funny, in 2002 I was living in New Orleans and it was perfectly fine to ride without a motorcycle helmet. I probably did anyhow about half the time. However, I got pulled over when I took the bicycle out becuase it was a law to have one on then. No ticket but thought it was crazy to mandate a helmet on a bicycle and not a motorcycle.
have to disagree with the beanie helmet comment. A DOT approved beanie will protect much more than the Styrofoam/plastic bicycle helmet. Just the shell itself is WAY harder than the plastic helmet. interior padding is more impact resistant also. Finally, eitherway, u have no facial or brainstem protection. Just my $.02
Notice I said "DOT". You know, the fiberglass yarmulkes that come with a "DOT" sticker that so many seem so fond of. Also, it's the styrofoam in the helmet that cushions the impact, not the flimsy, open-cell foam in the liner.
I like to be flexible , I've got 2 bicycle helmets [ mine look cool and are ] 3 arias and 1 shoe . My bicycle helmets have a DOT sticker, put it there myself . As a matter of fact, with a heat index today of about 105 it would be a good day for them .