Most discussions about vehicles and sustainability focus on fuel efficiency and emissions, and with good reason - there is an undeniable need to make our cars and trucks run leaner and cleaner.

But while fuel efficiency is important, it is only one part of the vehicle sustainability equation. Less than one-quarter of the energy from a tank of fuel is used to move a vehicle down a road; the rest of the energy is lost to engine and drive-train inefficiencies, to idling and to poor driving habits. Fortunately, the engineers responsible for creating more environmentally friendly and efficient designs are not limiting their focus to the technology of the engine; they have expanded it to the makeup and function of the entire vehicle.