Driving at 70 mph uses more fuel than driving at 50 mph by up to

Explanation: Your vehicle will use less fuel if you avoid heavy acceleration. The higher the engine revs, the more fuel you will use. Using the same gear, a vehicle travelling at 70mph will use up to 30% more fuel to cover the same distance, than at 50mph. However, don't travel so slowly that you inconvenience or endanger other road users.

Category: Safety and Your Vehicle

References: The Official DVSA Guide to Driving: Section 17