The most fuel-efficient speed for most cars is generally between 50 km/h and 80 km/h (around 30-50 mph), where aerodynamic drag isn't too high, and the engine isn't working too hard in low gears; however, the exact sweet spot varies by vehicle, so using your car's fuel economy gauge (if available) or driving smoothly in the highest gear at the lowest practical RPM on flat ground offers the best results.
For best fuel economy per distance in most modern cars: ~50--80 km/h (30--50 mph) is optimal; for practical highway travel choose ~90--100 km/h (55--62 mph) as the best compromise between speed and fuel use. Adjust RPM and gear to keep the engine in its efficient band and use smooth driving techniques.
Slow down
Your fuel usage will increase the faster you drive (due to increased air resistance), so where it's safe to do so, try to slow down. According to the AA, driving at 70mph uses up to 9% more fuel than at 60mph and up to 15% more than at 50mph.
For most fuel-efficient cruising do not exceed 50 miles per hour (DfT estimate). Most cars use about 10% less fuel when driven at 50mph rather than 62mph and a reduction in speed from 68mph to 50mph can reduce fuel consumption by 20%.
What is considered good fuel efficiency? Excellent/Highly Efficient: A combined rating below 7.0 L/100 km. This is often seen in smaller cars and electrified models. Good: A combined rating between 7.0 L/100 km and 9.0 L/100 km.
If a car uses between six and eight litres for every 100 kilometres, it's doing pretty good on gas. This includes smaller and some medium-sized cars. Cars that need eight to 10 litres to go 100 kilometres are average; they're not the best, but not the worst.
Typically, cars are most efficient at 45-50mph. As well as fuel economy differing from vehicle to vehicle, it is also dependent on a number of other factors such as tyre pressure, presence of roof racks, and driving style – all of which are covered in this guide.
Keep it close to 60 mph on the highway.
Highway driving that exceeds 60 miles per hour uses more fuel. According to the U.S. Environmental Protection Agency (EPA), every 5 miles driven above the 60 mph level is equivalent to paying 20 extra cents per gallon for gas.
It is likely to be geared for 2500 rpm or so at that speed, yet for maximum efficiency the engine should be running at about 1500 rpm (gasoline) or 1200 rpm (diesel) to generate that power as efficiently as possible for that engine (although the actual figures will vary by engine and vehicle).
Don't go too fast or too slow
You'll burn up to 15% more fuel at 100 km/h and 25% more at 110 km/h. That might tempt you to drive slow, but if you drive slower than 50 km/h, your engine would drop to a lower gear, thus using up more fuel.
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The 55-65 MPH Sweet Spot
Driving 70 mph instead of 60 mph can cost nearly $0.36 more per gallon. The 55-65 mph range is the best for most cars. It balances travel time and fuel use. Staying in this range is a top way to save on gas.
If you want to know which driving technique saves fuel, the answer is simple - driving sensibly. It's not always possible to be a perfect driver but driving sensibly can do wonders for your fuel consumption. This means accelerate steadily, brake lightly, and keep your ride nice and smooth.
Fuel efficient driving tips
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Fuel-efficient driving techniques
In most modern vehicles, a normal idle speed ranges from 600 to 1,000 RPMs. If your car is idling rough, however, the RPMs may jump up and down or fall below normal operating levels. An unstable idle can affect overall engine performance and may lead to stalling, poor fuel economy, and difficulty accelerating.
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The larger the wheel size, the more your fuel consumption. The simple reason is, that your vehicle combusts more power to roll bigger and broader wheels along the road surface.
Opt for cruise control Maintaining a constant speed on the highway is more fuel efficient than repeatedly accelerating. It also makes for a smoother ride. Use overdrive gears Your car's engine speed goes down in overdrive, which means gas savings. It's also easier on your engine and reduces wear.
Reducing your speed from 70mph to 60mph, when you're driving on the motorway, can save you up to 10% in fuel3 – getting you to the same destination for less!
Idle is one of the biggest culprits when it comes to fuel consumption. Idling is one of the main reasons the automatic Stop/Start technology was invented.
12L/100km is generally considered average to poor fuel economy, being on the higher end for most passenger cars but acceptable for larger SUVs, trucks, or during heavy city driving, with better efficiency being under 9L/100km and worse often exceeding 12L/100km. It depends heavily on the vehicle type (SUV vs. hatchback), driving conditions (city vs. highway), and engine size.
Generally speaking, yes. Cruise control can help you become more fuel-efficient and can help you save an average of 7-14% on gas thanks to its ability to maintain a continuous speed. In comparison, the constant change in acceleration and deceleration of the driver placing their foot over the pedals can eat more gas.
Anything that is listed as less than 6-litres/100km or more than 16.5km/1-litre is considered to be pretty good. The first (and most common) reference is litres per 100km (litres/100km). This is how many litres of fuel the car needs in order to travel 100km. You'll often see it referred to as 'fuel economy'.