When Is Fuel Consumption at Its Highest?

Fuel consumption is something most drivers are conscious of, especially with rising fuel prices and growing concerns about efficiency. So, when is fuel consumption at its highest?

In simple terms, fuel consumption is at its highest when you are driving in challenging conditions. Just as you burn more calories when your workout is more intense, your car burns more fuel when working harder. But what causes a car to work harder, and why does it have such an impact on fuel efficiency?

In this article, we will look at the factors that make fuel usage peak, what drivers can do to limit waste, and how to drive smarter for long-term savings.

In This Guide:

Understanding fuel consumption
Which driving scenarios and road conditions cause the highest fuel consumption?
Which vehicle characteristics influence fuel consumption?
Driving habits that increase fuel usage
How to minimise fuel consumption
Driving smarter to save fuel
FAQs

Understanding fuel consumption

To get a good understanding of when you might be burning more fuel than usual, it's important to understand the basics of your vehicle's fuel consumption:

How fuel consumption is measured

Fuel consumption is typically measured in miles per gallon (mpg) or litres per 100 kilometres (L/100 km). These metrics tell you how far a car can travel using a set amount of fuel. The lower the mpg or the higher the L/100km, the less efficient the car is.
Official ratings from manufacturers can be helpful in determining efficiency, but they cannot be relied upon exclusively. Real-world conditions often lead to different results. So, if you buy a car with a high fuel efficiency rating and then make it work a lot harder than it did in testing conditions, you might be in for a shock.

Factors that influence fuel efficiency

Many things affect how efficiently a car burns fuel. External factors like temperature, terrain, and traffic conditions can all increase fuel consumption. Vehicle design, engine size, and maintenance also play a major role.
Finally, one of the most important elements in overall fuel efficiency is the behaviour of the driver. Acceleration, braking, and route choice all directly affect how much fuel is used.

Which driving scenarios and road conditions cause the highest fuel consumption?

Let's start with the bad news: what increases fuel consumption?

Cold starts and short journeys

All exercise is easier after a warmup, even mechanical exercise! Engines are at their least efficient when they're cold. This is why you typically spend more on fuel during winter.

This is bad news for people who only use the car to nip to the shops and back. On a short journey, the engine rarely reaches its optimum temperature. This means that fuel consumption is relatively high over shorter distances. Repeated short trips can therefore bring higher fuel costs overall than longer, smoother drives.

Driving at high speeds

So, if short distances reduce fuel efficiency, is the answer to get on the motorway and put your foot down? Unfortunately, no. Fuel consumption rises sharply at higher speeds. To give you some idea, travelling around 75mph uses up to 18% more fuel than at 60 mph.

As your car speeds up, it encounters more wind resistance (think of the wind whipping past if you open a window on the motorway). The car has to work harder to combat this aerodynamic drag, which leads to increased fuel consumption.

Stop-start city traffic

Urban driving with lots of stopping and starting is another inefficient situation. Accelerating from a standstill repeatedly at traffic lights is very demanding on the engine, and idling in traffic wastes fuel without covering any distance.

Towing heavy loads

Towing a trailer, caravan, or another vehicle puts extra strain on the engine. The added weight means the car must work harder, leading to higher fuel consumption. This is especially noticeable on long journeys or when climbing a lot of hills.

Driving uphill or on steep terrain

When a car is climbing a steep hill, it has to fight harder against gravity. This requires extra power, which in turn demands more fuel. Drivers may also shift to lower gears when going uphill, which also raises the vehicle's fuel consumption.

Which vehicle characteristics influence fuel consumption?

What about vehicle factors that increase or reduce fuel consumption? What features should you expect to find in fuel-efficient cars?

Engine size and type

Larger engines usually use more fuel, though modern designs with turbochargers or hybrid systems do make a difference to this. The type of fuel can have an impact, too. Diesel engines often perform better for long journeys, while smaller petrol engines are more efficient for lighter, shorter trips.

Tyre condition and pressure

Under-inflated or worn tyres increase rolling resistance. This makes the engine work harder to move the car, leading to unnecessary fuel consumption.

Weight and aerodynamics

The heavier a vehicle, the more energy it takes to move it. Things like extra luggage, extra passengers, and roof racks can reduce aerodynamics and increase fuel consumption. For example, a roof box can add 22% to fuel consumption while driving at 62 mph. Even a set of empty roof bars can add around 7%.

Driving habits that increase fuel usage

You can reduce fuel consumption by making a few tweaks to your driving behaviour:

Aggressive acceleration and braking

Sharp acceleration followed by heavy braking is one of the fastest ways to waste fuel. Smooth, steady driving at a constant speed is much more efficient and reduces strain on the engine.

Excessive idling

Leaving the car running while it's stationary (for example, while sitting in traffic) wastes fuel with no benefit. Even modern engines can burn a surprising amount of fuel while idling.

Incorrect gear use in manual cars

Staying in a low gear longer than necessary means the engine revs a lot more. This increases fuel use. Try shifting up earlier, without labouring the engine, to save fuel.

How to minimise fuel consumption

How, in practical terms, can you implement these fuel-efficient changes into your regular driving behaviour? Here are some tips:

Planning efficient routes

Choosing routes with fewer stops, less congestion, and shorter distances can slash your fuel use. Many sat-nav systems now include eco-routing options.

Using cruise control effectively

On motorways, cruise control can help maintain a consistent speed, which prevents unnecessary acceleration and braking. However, bear in mind that cruise control is less effective on hilly or urban routes.

Maintaining steady speeds

Consistent driving is one of the best ways to save fuel. Fluctuating speeds and unnecessary overtaking can quickly raise consumption levels.

Driving smarter to save fuel

All in all, fuel consumption is at its highest in situations where the engine is under strain, such as during cold starts, high-speed driving, stop-start traffic, towing, or climbing steep hills. The condition of your vehicle and your driving style also play a major part. By maintaining the car, planning routes carefully, and adopting smoother driving habits, you can use a lot less fuel, and drastically cut your car's running costs.

If you want to learn more about fuel-efficient driving, MoneyExpert has a range of motoring resources to help. Or, to bring running costs even lower, use our simple quote comparison service to find the best possible deal on your car insurance.

FAQs

Does air conditioning increase fuel consumption?

Yes. Air conditioning puts extra load on the engine, which increases fuel use, especially at lower speeds.

Is fuel consumption higher in winter?

It can be. Cold engines take longer to warm up. Heaters, lights, and other electrical systems also add to the strain.

Does premium fuel improve efficiency?

For most cars, no. Premium fuels can benefit high-performance engines, but for standard vehicles they rarely make a noticeable difference.