Let’s say we are driving from A to B. The beginning of the drive starts with a steep uphill, but the remaining drive is long and downhill. Points A and B are the same elevation. Which direction (A to B or B to A) is more energy efficient (less fuel consumption)? Or is it maybe equal?

Question

EDIT: I am discussing real world scenario in a car. I will definitely check the fuel consumption next time I drive from Reykjavík (B) to Hveragerði (A) (and back) here in Iceland. Thanks for great answers 🙂

In: 1

Answer 1

Assuming a petrol/diesel car then the short uphill and long downhill would use less fuel if you were to turn off the engine and roll down the downhill part, as you would be running the engine for a shorter time and just turning over an engine uses fuel even when not providing force to the car.

In reality if you’re driving normally or using an electric car, probably close to even.