Driver Feedback

Have the option to have the car monitor your driving habits and offer suggestions for improvement.

-Recognize daily routes and schedules, and suggest alternatives.
-Remind you how often you do hard breaks and accelerations.
-Your cruising speed vs optimal
-Somehow track your MPG, tire pressure, etc. if it's unusual, give you a notice of a possible mechanical issue.

Progressive insurance has a Snapshot problem that collects similar data and has a nice webpage for you to review.
I also think this is a great idea. Maybe dealers should offer a free "class" to folks with older cars on the best ways to improve fuel economy. Such as my girlfriend in her 2009 fusion where she can only manage 16-17 MPG, and I consistently get 20+