Fuel is a huge expense for many Americans, with the average driver shelling out just under $2,000 a year on gas, according to the Bureau of Labor Statistics. People with long commutes or higher costs of living can spend much more.
Gas guzzling also has an impact on the environment, spewing pollutants into the air that affect air and water quality, which eventually harms not only people but also plants and wildlife.
The good news is that there are dozens of steps you can take to improve fuel economy, protect the planet and keep more cash in your wallet. The bad news? A surprising number of widely known fuel saving tips have no basis in fact. As cars and technology have changed over the decades, people have kept on believing the same old fuel economy myths, rather than switching to strategies that actually make a difference.
That means you could be sweating it out in a broiling car because you're convinced that using the AC or rolling down the windows will blow your gas budget. It might also mean you're missing out on easy opportunities to cut fuel costs, like maintaining the right tire pressure, in favor of things that actually have zero impact on gas mileage.
Think you have what it takes to separate fact from fiction? Take our fuel economy myths quiz to find out!
Thanks to continuous improvements in auto technology, smaller cars aren't always the most efficient. In fact, half of the cars on the Environmental Protection Agency's (EPA) list of most efficient vehicles for 2016 are midsize or larger.
In modern vehicles, cars with an automatic transmission often have the same or better mileage as the same model with manual transmission.
Idling costs between 1 and 2 cents per minute in gas and can use one-third to one-half gallon of gas per hour.
Aggressive driving can reduce gas mileage by 5 percent on city roads and as much as 33 percent on the highway.
Every 5 miles per hour over 50 miles per hour adds about 12 cents to each gallon of gas you buy.
Starting a modern vehicle uses as much gas as 10 seconds of idling, so it almost always makes sense to turn your vehicle off rather than leave it on while you're waiting.
A top-mounted cargo container cuts fuel efficiency by 2 to 8 percent in the city and as much as 25 percent on the highway.
Extra weight wastes gas, and every 100 pounds you carry can reduce gas mileage by 1 percent.
By helping you maintain a constant speed, cruise control saves you gas and money when you're driving on the highway.
If you properly maintain your vehicle, you shouldn't expect to find any significant decrease in fuel economy, even after 10 to 15 years of ownership.
In modern vehicles, replacing a dirty air filter may improve vehicle performance, but it's unlikely to improve fuel economy all that much.
While you should always use premium if your car requires it (check the manual), premium fuel does not improve mileage in the average vehicle.
A 10-percent ethanol blend decreases fuel efficiency by around 3 percent thanks to the lower energy density of the ethanol.
The average driver will naturally improve fuel economy by 3 percent when using a driver feedback device, while a person who uses this device primarily to improve mileage can boost efficiency by as much as 10 percent.
A rear-mounted cargo container only reduces mileage by 1 to 2 percent in the city and 1 to 5 percent on the highway.
Replacing a damaged oxygen sensor — a relatively simple fix — can improve fuel economy by as much as 40 percent.
Making sure your tires are properly inflated can boost fuel economy by 3.3 percent on average.
Every 1 pound-force per square inch (6,895 pascal) decrease in tire pressure equates to around a 0.03 percent decline in fuel economy.
Using the recommended motor oil for your vehicle improves fuel economy by an average of 1 to 2 percent -— that's like saving 2 to 3 cents per gallon.
Several short trips can actually consume more fuel than one longer trip covering the same total distance. This is especially true if your vehicle is cold when you start it.
Fuel economy decreases by 12 percent when the temperature drops from 70 degrees Fahrenheit (21 degrees Celsius) to 20 degrees Fahrenheit.
The best way to warm up a car is to drive it. Allowing the car to sit idle simply wastes gas.
If your vehicle has some problems or fails an emissions test, you can expect to boost fuel efficiency by 4 percent with a proper tuneup.
Using your air conditioner can reduce fuel efficiency by as much as 25 percent during the peak of summer.
Rolling your windows down has a dramatic effect on fuel economy on the highway. To maximize efficiency, use your air conditioning on the highway and roll your windows down to cool off while driving in the city.
Because most gas stations store gas underground, the idea that you'll get more gas for your money in the cooler morning hours is no more than a myth.
An EPA review of more than 100 devices and products that promise to improve fuel economy found that none actually have any significant impact on mileage.
In a Consumer Reports test, lowering the tailgate or adding a tonneau cover to a pickup actually made fuel economy worse, not better.
Fuel economy tests and ratings don't always reflect real-world performance and are designed as a way to compare the relative fuel efficiency of different vehicles.
The average U.S. household spends around 5 percent of their money on gas, which breaks down to almost $2,000 per household in 2015.