Speaking of being really careful and aware, I just met a guy who has a really nice 3-wheel recumbent "tadpole" trike that he only uses on the local bike path that is flat as a pancake and rides around 12 mph. He religiously wears a helmet. He made me realize that there are certain cycling situations where I would likely NOT bother wearing a helmet. (And it kinda made me want a tadpole trike dagnabbit)