Do you lose efficiency by accelerating and decelerating? For instance, going faster when no cop is in sight, and slowing down when not much road ahead can be seen? What about on hills, is it better to maintain speed than slow down on the uphills and speed up on the downhills? Another way to ask is to say whether it’s better to maintain gas pedal position or speedometer position. And if there’s a difference, is it significant?

What is the price for accelerating faster (pedal to the metal) vs. slow acceleration? This probably depends on manual vs. automatic.