If this is the case then WHY THE HECK are we letting people Under 18 Drive at all ! ......
IMO No one should drive a Real car till 21 .... Boom there I said it.....
Some states have changed their licensing for this very reason. Michigan has a "graduated driver's license" program that restricts teen driving and then gives them more and more flexibility as they age and prove themselves.
http://www.michigan.gov/sos/0,4670,7-127-1627_60169_60175---,00.html
When I first started driving, we got a permit at age 15 and then a license at age 16. There weren't any restrictions, but it was a probationary license - after a year (IIRC) without incidents, you were taken off probation.
It's wildly different now. There was talk of increasing it to 18, but they realized having parental supervision and gradually-increased permissions during those first two years is more helpful than giving someone a license at 18 and letting them go willy-nilly, especially since some kids start college when they're 17 and don't live anywhere near their parents.
Plus parents are tired of being taxi drivers!
This is probably the biggest practical stumbling block. In areas where you've got viable public transit, raising the driving age might work. Might. But I'll use myself as an example here:
When I was 16 my mother passed away, my father being previously deceased. I moved in with my (non-driving) grandmother about 20 miles away. For a week during the previous winter, I had lived with her when my mother was in the hospital; being 15 at the time, I couldn't drive myself, which meant getting someone else to drive (though I had my permit, I didn't ask to drive...I was working on a paper that week, visiting my mother in the hospital, and was generally not in good shape to do a lot of driving due to the piled-up circumstances). At other times, if I couldn't get my mother into the car, I couldn't drive to school when I had my permit (and this was, on one or two occasions, at issue IIRC).
Had I been unable to drive to school, I'd either:
(1) Have had to change schools and probably lost touch with a lot of my friends at a very bad time, had to drop almost all my existing social activities, etc. OR
(2) Have had to live with my grandfather, at least during the week. As it was, we tried this...it was a clunky mess of an operation, and while I lived in my old house with him during the week, it was less-than-ideal.
Public transit was (and is, in this sort of situation) a non-option if I was going to maintain any extracurricular options (and even then, a multi-hour commute would have been necessary for the most part).
Now, it would seem to be possible to simply issue a severely restricted "special circumstances" license for kids with either only one parent/guardian/capable adult or who are in a similar living situation (two parents, but one can't drive for health reasons and the other has to drive
them around), but there's no mechanism for that in the law pretty much anywhere that I know of now. Basically, you've got enough situations where parents
can't play taxi driver and where schools aren't in a position to offer continual bus service all afternoon, and where public transit either doesn't exist or is horridly impractical at best (rural areas come to mind) that pushing the license age much past 16 runs into practical problems...and as has been pointed out, you've got enough 17-year-olds in college (either due to birthday timing or double-promotion...this share of the population may be modest, but it is still significant) or who take classes at community colleges, etc. (i.e. in situations the school bus won't cover) that you'd need a
lot of exceptions in the law to make a higher driving age work.