I agree with the premise of raising the age everywhere, of course, I'm not 16 or 17 anymore (by a longshot). I might feel differently if I was.
Many European countries already have an age limit. For one, this takes cars off the road, which is never a bad thing for both the environment and traffic control. But Europe also has much better public transit and much smaller land mass to deal with.
In Hawaii specifically, and I've only been there twice, mind you, traffic was pretty bad in and around Honolulu, where the bulk of the state's population is. The road system they have there was never designed for the number of vehicles it currently handles, in my opinion.
As a teacher, I like the idea of not having students younger than seniors driving to school each day. It eases parking issues, but also, a sophomore in high school is easily distracted behind the wheel, especially with friends in the car.