How Do Vehicle Aerodynamics Change Gas Mileage?

March 9th, 2023 by

Aerodynamics of a Car in a Wind Tunnel

The aerodynamics of your vehicle can change the fuel efficiency of your gas tank. One key measurement comes from the coefficient of drag, a number between 0 and 1 that quantifies how the air moves around your vehicle as it travels down the road. The lower the coefficient of drag, the better your car moves through the air. 

We’ll take a close look at how the aerodynamics of your car can alter the gas mileage you get.

Related Post: 7 Most Popular Car Modifications

How does drag affect gas mileage?

The coefficient of drag is just one part of the equation for aerodynamics. Speed, the weight of the vehicle, the frontal area, and air density also come into play. As you go slower, aerodynamics is less of a factor in gas mileage. If your vehicle is heavier, it might not move through the air as fast. The curvature and surface area of the front part of your vehicle can also affect your vehicle’s aerodynamic profile.

Max Schenkel, technical fellow of aerodynamics for General Motors, told Edmunds that a change in the drag coefficient of just 0.01 changes the combined fuel economy of a vehicle by 0.1 mpg. If you drive 150,000 miles with a vehicle, that one-tenth of a mile per gallon adds up quickly. At $3 per gallon and 30 mpg, you could save up to $1,000 driving that 150,000 miles

Another thing to consider is that a higher speeds, aerodynamic drag can account for half or more of the fuel your vehicle uses, according to Haynes. So, aerodynamics becomes more of a factor for fuel consumption as you go faster. This is one reason cars can get 30 mpg or more on the highway versus figures in the low to mid-20s for SUVs and pickup trucks.

Things That Are Bad for a Vehicle’s Aerodynamics

As you increase your speed, aerodynamics become more apparent when gauging gas mileage. Consider these factors when looking to get better gas mileage at higher speeds.

Windows Down

You’ve heard the joke about 4×60 air conditioning coming from four windows down at 60 mph (before air conditioning was standard on vehicles). Nowadays, having the windows down at high speeds can reduce your gas mileage because it makes the airflow less efficient as it moves around your car. Your engine must work harder to maintain the same speed as if your windows were rolled up.


Hauling a camper, utility trailer, or boat is one main reason you own an SUV or pickup truck. Traveling at high speeds while towing something alters the aerodynamics of your vehicle while also increasing the weight, both of which can decrease your fuel efficiency.

Rooftop Cargo Carriers

Maximizing your vehicle’s cargo capacity includes having a trailer behind you, loading up the inside, and possibly having a cargo carrier on top. The cargo carrier on top changes the aerodynamics of your car, SUV, or minivan and increases the drag. You’ll have lower fuel efficiency compared to traveling without the cargo carrier on top.

Related Post: Windows Down vs. Air Conditioning for Fuel Efficiency

Find Vehicles With Excellent Gas Mileage in Springfield, MO

Looking for a great new vehicle with great fuel efficiency? Contact Thompson Sales in Springfield, MO, or call (417) 763-6811. We’re happy to help in any way we can!

Posted in Driving Tips