On a cold winter day, before driving the vehicle around, you may leave the car running for at least five minutes…But is this advice even valid? Honstein Oil has the answer. No, it isn’t anymore.

But, Why?

Idling your car means to run the engine without actually going anywhere. In a study of costly car myths from 2009, researchers found that Americans thought they should do this for at least five minutes before driving if temperatures were below freezing. Negatory! It is true that vehicles become at least 12 percent less fuel efficient in the winter, and it takes longer for the engine to heat up, but that doesn’t mean you need to idle your car.

The last time it was actually necessary to do so was during the 1980s and early 1990s, when older cars relied on carburetors. A carburetor’s job was to mix the correct amount of gasoline and air for the engine to run properly.

Why This Changed

Carburetors became out of date when electronic fuel injections were introduced to the industry. These use “sensors to supply fuel to the engine and get the right air and fuel mix. … The sensors monitor and adjust to temperature conditions.”( The Washington Post ) So, idling a car today provides no benefits to modern cars. According to the Environmental Protection Agency and Energy Department elaborate, “the engine will warm up faster being driven.” Anytime you idle your car, you are wasting fuel and contributing to greenhouse gas emissions.

Not only is idling an environmental fault, depending on where you live, it might also be illegal. For example, in Ohio, idling your car at all is strictly forbidden. The engine anti-idling law in Washington, D.C. states that: “Motor vehicles powered by gasoline or diesel are not allowed to idle for more than three minutes while the vehicle is parked, stopped or standing. Any person or organization owning or operating a vehicle seen violating this regulation will be issued a civil infraction ticket for $1000 for a first-time violation.” If you’re wondering whether or not you can legally idle? Look up your home state on the EPA’s anti-idling regulations.