If you have teens about to drive, visit C's Space. She's got two teens, one 18 and one 17, both driving, and apparently both driving her nuts!
I have no problem with raising the driving age to 21. If you can work and show you're responsible enough to earn some money, you might even be responsible enough to own/drive a car. Having/driving a car is not an inalienable right, despite most teens' opinions - it's a privilege, one to be earned.
The problem is many teens don't earn the privilege. They're given cars upon graduation, or upon turning 17. While there are plenty of responsible 17-year-olds out there who have been working since they could work, it's not the majority of them.
I signed her petition. If you agree, drop her a line!
And I know there will be people out there who will argue that if you're old enough to fight for this country, you should be old enough to drink and/or drive. So raise everything to 21 - you become an adult when you turn 21. Period. End of argument.