That, and just let kids walk home. It's good for their muscles.
If three miles sounds like not a big deal, it certainly is when you have short legs, a backpack full of books, and uncooperative weather. I was lucky enough to walk to/from school for most of my schooling. It was only around one mile and it still took 30 minutes. As an adult I would probably balk at a 90-minute commute.
80% of kids live too far away for walking to be feasible.
Many should be able to walk almost as fast as loading up the car, waiting in the queue, etc.