This is how we drive at different speed regulations
(swedish signs in example)
At these higher speeds we drive in 80 km/h (50 mph).
At these lower speeds we drive as fast as we are allowed to,
which means we keep the speed limits on the signs.
Why? The most fuel efficient speed for modern cars is around 70-80 km/h (44-50 mph). The car is then run in the highest gear and at as low rpm (revolutions per minute) as possible. The wind resistance has not yet built up so hard either. In other words, 70-80 km/h is the speed where we get the lowest fuel consumption and the lowest emissions.
The most climate friendly way to drive would be to keep the speed at 80 km/h (50 mph) all the time, everywhere. But of course that wouldn’t work. The lower speed limits are there for safety reasons. So the best combination between efficient fuel consumtion and safety is to drive in Climate Speed. Keep the lower speed limits and don’t drive faster than 80 km/h (50 mph).
Try it, and see for yourself how little extra time you need to invest and how much your fuel consumption goes down.