Our 15 year old is 6' tall - unlike his mother, he won't have a problem seeing over the dashboard when he starts to drive.
This is a funny story I have to share: Both girls learned to drive on my yellow Chevy van. Kari was practicing driving with her dad in the parking lot of her high school. He wanted her to back up in a straight line. She wove from one side to the other. He told her to imagine cars parked in the parking spaces and not to hit any of them. She still swerved.
He had her stop and asked her how many cars she thought she'd hit. Her answer was, "I don't know, Dad, I can't even see the roof of the high school!"
Jack scrunched down and looked back from her level and sure enough, he could only see air!
Needless to say, she used phone books, pillows and anything else that would make her tall enough to see what she was doing.