The vast majority of teenagers are reckless in their cars. They don't think they are but they are and that is why it is so expensive to insure them. Add the recklessness to lack of experience and the many distractions they encounter (music, friends, cell phones) and this creates the perfect storm so to speak.
I wouldn't say that. I am 20, and not once did I ever CAUSE an accident, when I've been hit by three people almost 2x's my age. It doesn't ALWAYS matter the age, rather the attitude of the person. No, I am not denying that teens are sometime reckless, but adults can be, too. I believe that because since they've been driving for so long, they don't pay as much attention. So it really does go both ways.