Factors That Affect Fuel Efficiency


Fuel efficiency measures how far a vehicle can travel on a certain amount of fuel. According to the MIT School of Engineering and HowStuffWorks, improving fuel efficiency can reduce our dependence on oil, lower gasoline prices, and limit climate change.


The EPA now lists a car’s fuel consumption (gallons per 100 miles) on its Monroney window sticker. Using this number illustrates a linear relationship and helps drivers understand their impact on fuel economy.

Vehicle Type

A vehicle’s fuel efficiency depends on a variety of factors, including what type it is. Cars get better fuel efficiency than trucks or vans of the same size. The vehicle’s weight also has a major impact on fuel efficiency. Reducing the weight of onboard luggage and cargo can help a vehicle achieve better gas mileage. The vehicle’s drivetrain can also influence its fuel efficiency. Four-wheel-drive vehicles use more fuel than 2-wheel-drive cars because the engine has to power two sets of wheels. A car’s aerodynamic drag and rolling resistance can also be factors. An operator must properly maintain a vehicle to ensure it operates smoothly and efficiently.

Changing the way a fleet uses its vehicles can also improve fuel efficiency. Fleet managers can encourage drivers to be more efficient by providing incentives and offering training and feedback. They can also change routing so that drivers are taking the most efficient path possible.

The United States and some other countries measure fuel efficiency in miles per gallon (MPG). A car’s MPG will be displayed on its window label. However, other countries use metric units and may display fuel efficiency in kilometers per liter (km/L) or litres per 100 kilometers (L/100 km). The latter unit is often used for imported vehicles because it provides a comparable measure to the MPG that American drivers are familiar with.

Fuel Source

A fuel is any substance that releases energy, most commonly through chemical means like combustion or nuclear means such as fusion. It is contrasted with other sources of power, which typically store energy as potential, or mechanical, work (such as flywheels, springs, compressed air and the potential energy in a battery).

The most common on-road motor vehicle fuel is gasoline, followed by diesel fuel and then natural gas. Alternative fuels are growing in popularity, including liquefied 초보운전연수 petroleum gas (LP gas), biodiesel and electric vehicles powered by plug-in hybrid or all-electric batteries.

Fuel efficiency is a measure of how far a motor vehicle can travel on a unit of fuel—in the United States, it is measured in miles per gallon, or mpg. Other nations use liters per 100 kilometers or other measurements.

The fuel efficiency of your vehicle depends on how well you drive, and on the driving conditions. Aggressive driving and rapid acceleration will cause your engine to burn fuel more quickly, while smooth and steady driving improves mileage. The EPA notes that idling your car for long periods also negatively impacts fuel efficiency, as the engine is not working at its optimum level. Adding weight to your vehicle also decreases its fuel economy, as the extra weight requires more fuel to move the vehicle around. However, reducing the amount of parasitic losses—energy lost through friction, braking and other non-engine sources—can boost your fuel economy.

Vehicle Design

The final design of the vehicle has a significant impact on its fuel efficiency. Engineers who specialize in building cars will tweak the original vehicle design to make it cost less and go into production faster. This will involve details like how the individual parts fit together and which parts are used (sourcing). The engineering team may also lay out a plan for each stage of construction, from the bare frame to the finished car.

Streamlining the vehicle’s aerodynamic drag is another way to improve its fuel efficiency. A large amount of traction energy is lost through friction, so engineers try to minimize the frictional losses in a vehicle. Airflow around the car is deflected by properly sized and shaped spoilers. Thinner wheels and tires with lower rolling resistance help reduce road friction.

Newer engines, transmissions and power trains are designed to be more efficient. These improvements can significantly increase the average fuel economy of a fleet of vehicles.

The vehicle’s weight also affects its fuel efficiency. Heavy vehicles require more fuel than lighter ones to travel the same distance. Increasing the amount of lightweight materials and reducing the number of heavy parts in a vehicle can drastically improve its fuel economy. The driver’s driving habits also have an impact on fuel consumption, which is why it is important to drive in a smooth fashion and avoid sudden acceleration and braking.

Driving Habits

The fuel efficiency of your car or truck can be affected by how you drive. Rapid acceleration and slamming on the brakes use up more fuel. Using the brakes too often also puts unnecessary wear on the car’s components.

You can significantly improve your gas mileage by driving more gently and prudently. Obeying the speed limit, accelerating and decelerating smoothly, and keeping up with traffic flow are all simple ways to save fuel and increase your mileage.

It’s also important to be mindful of how much your vehicle is idling. Idling vehicles waste a significant amount of fuel and collectively consume several billion gallons per year.

If you are idling for more than 30 seconds, turn the engine off and start your trip over again. It’s also best to maintain a safe distance behind the vehicle in front of you, so that if they need to slow or stop quickly, you won’t be following them too closely and losing more fuel.

On the highway, keeping your speed steady and avoiding excessive idling is key to fuel-efficient driving. The more you vary your speed, the more fuel is used to overcome wind resistance. It is also more fuel-efficient to stay in higher gears rather than allowing your engine to drop to lower ones. This is because your engine works harder when it is in a lower gear and therefore uses up more fuel.