1)Reduce the speed limit for all motorized traffic to 25 mph except on highways where it would still be limited to 45, the best speed for gas milage.
2)Improved public transportation all around. Buses with bike racks that run 24/7, light rail, long distance high-speed trains.
3)Eliminate all government spending on auto infrastructure including subsidies for parking.
Too extreme? Maybe, but its my fairy tail.