Which Driving Technique Can Save Fuel? Speed Comes First

Holding a steady, lower speed on fast roads saves the most fuel. The Department for Transport’s fuel consumption curves show a diesel van uses 14.5% less fuel per mile at 60 mph than at 68 mph. Smooth driving, less idling and correct tyre pressure also help, but speed is the only one you can put a firm number on.

Which driving technique saves the most fuel?

Driving more slowly and steadily on motorways and dual carriageways saves the most, because air resistance rises sharply with speed. At motorway speeds, a growing share of the energy your engine burns goes into pushing the vehicle through the air. Every extra mile an hour costs more than the last.

The Department for Transport (DfT) publishes fuel consumption curves in its TAG data book (v2.03, May 2026, table A1.3.8). They give fuel used per mile at each average speed. Here is how much less fuel per mile you use at the lower speed:

Vehicle	70 to 60 mph	68 to 60 mph	68 to 56 mph
Diesel van	not covered	14.5%	20.0%
Petrol van	16.1%	12.6%	16.4%
Diesel car	9.6%	7.5%	10.1%
Petrol car	8.9%	6.8%	8.8%

DfT’s diesel van curve stops at 68 mph, which is why that column is blank. We do not quote a diesel van figure above that speed.

What is the best order of driving techniques for saving fuel?

Speed first, then smoothness, then the habits that waste fuel while the vehicle is barely moving. This ranking is our judgement. Only speed has published figures we can stand behind, so the rest are named without percentages.

1. Drive at a steady, lower speed on fast roads. The DfT figures above. This is the largest single lever and the one that works on every journey.
2. Anticipate, and accelerate and brake gently. Reading the road ahead means you lift off early instead of braking late. Hard acceleration burns fuel you then throw away as heat in the brakes.
3. Stay in the highest sensible gear. Low revs at a steady speed use less fuel than high revs at the same speed, provided the engine is not labouring.
4. Cut idling. An idling engine does zero miles per gallon. Switch off when you are loading, waiting or parked up.
5. Keep tyres at the right pressure. Soft tyres drag. Check them against the vehicle handbook.
6. Carry less. Take out racking, tools and stock you do not need on today’s job, and remove roof bars when they are not in use.
7. Plan the route. Fewer stops, fewer junctions and less congestion all mean less fuel.

Why does speed matter more than the other techniques?

Speed matters more because it is the one technique that changes the physics of every mile, while the others trim waste around the edges. Aerodynamic drag increases with the square of speed. Smooth driving cannot undo that.

There is a second reason. Speed is a choice made hundreds of times a day, on every motorway slip road. Techniques like anticipation take skill and attention. Easing off the accelerator takes neither.

What is the most economical speed to drive at?

It depends on the vehicle, and it is lower than most drivers think. The DfT curves put the most economical speed for a diesel car at about 45 mph, a petrol car at about 50 mph, a petrol van at about 49 mph and a diesel van at about 39 to 40 mph. A rigid HGV is about 44 mph.

Nobody can drive a motorway at 40 mph. The practical point is that fuel use per mile falls as you move towards those speeds from above, so 60 beats 68, and 56 beats 60.

Does the gain from a driving technique last?

It lasts only as long as the driver keeps doing it. A technique is a habit, and habits slip when drivers are tired, late or behind schedule. This is the difficulty fleets run into with advice on how to save fuel: the advice is correct, but it depends on every driver, on every journey.

That is why the evidence on speed control matters. A 2009 study by CE Delft for Novem fitted speed limiters to 177 vans and 30 trucks of 3.5 to 12 tonnes across 16 companies for a year. It recorded a 5% average fuel saving. That is an average across the whole fleet, including miles below the cap where the limiter changed nothing.

How much will a technique save my fleet?

It depends on the share of miles driven fast. A van that spends most of its day on 30 mph roads gains little from a motorway speed cap. A van doing long A-road and motorway runs gains a lot. Our speed and fuel calculator takes your vehicle type, mileage, fuel price and the share of miles you drive at speed, and gives you the litres and pounds.

For a worked example with this week’s diesel price, see 70 vs 60 mph fuel cost for a van fleet. For the full list of what to measure, use the fleet fuel savings checklist.

Frequently Asked Questions

Which driving technique can help you save fuel?

Driving at a steady, lower speed saves the most, especially on motorways and dual carriageways. The Department for Transport’s curves show a diesel van using 14.5% less fuel per mile at 60 mph than at 68 mph. Gentle acceleration, early braking, less idling and correct tyre pressure add to that.

What driving technique helps save fuel besides slowing down?

Smooth acceleration, anticipating the road ahead, staying in a sensible high gear and switching off instead of idling. Keeping tyres at the right pressure and carrying less weight also help. None of these has a single published figure that applies to every vehicle, so measure them against your own fuel data.

Is it better to drive at 60 mph or 70 mph to save fuel?

60 mph uses less fuel per mile. For a petrol van, the DfT curve shows 16.1% less at 60 mph than 70 mph. For a diesel car it is 9.6% less. Diesel vans are covered up to 68 mph, where the saving at 60 mph is 14.5%.

Does a speed limiter save fuel?

Yes, when the vehicle would otherwise travel faster than the cap. In the CE Delft trial, speed limiters on vans and light trucks gave a 5% average fuel saving over a year. The saving for your fleet depends on how many of your miles are driven above the cap.

Does driver training make a lasting difference?

Training helps while drivers apply it. Without something that holds the behaviour in place, habits tend to drift back. A speed limiter holds the top speed whether or not the driver remembers the training.

Cut your fleet’s fuel bill

Find your own number with the speed and fuel calculator. Enter your vehicles, annual mileage and the share of miles driven at speed, and it shows the fuel and cost difference at a lower cap using this week’s prices.

A speed cap works on every journey without the driver having to remember it. The Department for Transport’s fuel consumption curves show a diesel van using 14.5% less fuel per mile at 60 mph than at 68 mph. How much of that reaches your bill depends on how many of your miles are driven above the cap.

Talk to us. AutoKontrol has made speed limiters in Britain since 1985, with nationwide installation where we come to you. Book a free consultation or get a quote.