Explanation: Your vehicle will use less fuel if you avoid heavy acceleration. The higher the engine revs, the more fuel you'll use. Using the same gear, and covering the same distance, a vehicle travelling at 70 mph will use up to 30% more fuel than it would at 50 mph. 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