When I was a kid (under 16), I rode my bike everywhere, and like you guys, my parents weren't worried about where I was for hours at a time.

But I distinctly remember it being very uncool to ride a bike once you hit driving age --- this was in the 80s. If you didn't have a car, you bummed a ride off a friend --- you wouldn't be caught dead on a bike. And you had to continuously and endlessly "cruise" parking lots on the weekends to show the other kids that you had a car. Of course, this was when gas was under a $1 a gallon