"I always wear a helmet. If I were without it, I would feel vulnerable and ride more carefully." <-- if you are one of these people, you need to reexamine your safety regime.

You are firmly in the "I am under the mistaken impression that a helmet will do more for me in the event of a crash than it was designed or tested for" camp.

You are riding unsafely and are more likely to crash and possibly suffer a head injury.