I think the optimal speed for fuel efficiency for most vehicles is around 55 mph, give or take a 2-3 miles per hour. Edit: I was mistaken, this is from the Gua

I think the optimal speed for fuel efficiency for most vehicles is around 55 mph, give or take a 2-3 miles per hour. Edit: I was mistaken, this is from the Guardian: > The Energy Saving Trust says that the most efficient speed you can travel in a car in terms of achieving the best fuel economy is 55-65mph. Any faster, though, and the fuel efficiency decreases rapidly. For example, driving at 85mph uses 40% more fuel than at 70mph (oh, and it's illegal too). https://www.theguardian.com/environment/green-living-blog/2011/mar/25/hypermiling-tips https://www.theguardian.com/environment/green-living-blog/20...