Fuel Efficiency vs Speed (why 60mph is the best speed)

Fuel Efficiency vs Speed (why 60mph is the best speed)

How does fuel-efficiency change as you drive faster? In the video, we drive the exact same route at 50, 55, 60, 65, and 70mph to see how fuel-efficiency is affected. The results show that driving at 70mph uses 30% more fuel than the same journey driven at 50mph. But driver behaviour is also a factor: and 60mph seems to be a sweet-spot.