Does Cruise Control Actually Save Fuel?

The Myth of Cruise Control

Cruise control was designed to make long motorway journeys less fatiguing by locking your car into a constant speed. For years, drivers have assumed that because the car is driving smoothly without human error, it must be the most fuel-efficient way to drive. The truth, however, depends entirely on the shape of the road.

When Cruise Control Saves Fuel

If you are driving on a perfectly flat stretch of motorway, cruise control is a hypermiling dream. The computer can maintain a steady throttle position with microscopic adjustments that a human foot could never replicate. This constant, unwavering momentum prevents unnecessary acceleration and braking, saving significant amounts of fuel.

When Cruise Control Wastes Fuel

The problem arises the moment you hit a hill. Cruise control is utterly blind; it does not know a hill is coming, and it has one strict directive: maintain the target speed at all costs.

When a car on cruise control hits an incline and begins to slow down, the computer panics. It aggressively forces the throttle open (often downshifting in an automatic) to force the car back up to speed as fast as possible. This sudden, violent surge in RPM burns a massive amount of fuel.

The Hypermiler's Solution

To get the best MPG, use cruise control on flat roads. When you see a hill approaching, turn it off. Allow your car to naturally lose a few miles per hour as you climb the hill using a steady, light foot on the pedal, and then regain that speed using gravity on the way back down. Pair this smart driving style with the cheapest local fuel prices to maximize your savings.

Local prices differ far more than most drivers expect. For a worked example, see current petrol prices in Manchester.

Cheaper fuel beats better mileage

Driving technique is worth a few percent on consumption. Choosing the right forecourt is often worth more. With more than 10p a litre between the cheapest and dearest stations in most towns, a two minute check before you set off usually saves more than a month of careful driving. We publish live prices for 2,283 UK towns - find fuel prices near me or browse prices by region.