Many people ignore the state law that makes it illegal to idle your car or truck for more than three minutes, even though it can be harmful to their vehicle, their health, their finances, and the environment.

It is “fuelish” to worry about how much it costs to fill the tank and then waste gas by idling. Idling a car uses up to a half gallon of gas per hour and even more for an SUV or pickup truck. A vehicle gets zero miles per gallon while idling, so that’s like burning money.

It may not seem like following the law by idling no longer than three minutes would make much of a difference, but researchers for the U.S. Department of Energy (DOE) reported that idling from heavy-duty and light-duty vehicles wastes about six billion gallons of fuel a year.

“About half of that is attributable to personal vehicles, which generate around 30 million tons of [carbon dioxide] every year just by idling,” according to the May 2015 report by the Alternative Fuels Data Center of the DOE.

“While the impact of idling may be small on a per-car basis, the impact of the 250 million personal vehicles in the U.S. adds up. For saving fuel and reducing emissions, eliminating the unnecessary idling of personal vehicles would be the same as taking 5 million vehicles off the roads,” the report said.

The damage that idling causes to your engine can be more costly than wasted gas. While a vehicle is idling, the fuel is not properly combusted, preventing the engine from reaching an optimal temperature. That can cause residue to develop on valve stems, piston rings, cylinder walls, and the catalytic converter, thus requiring repairs.

Idling also creates air pollution. Every burned gallon of gas produces more than 20 pounds of greenhouse gases. An idling vehicle creates far more pollution than one traveling at 30 miles an hour, contributing to haze, acid rain, and climate change. Breathing in exhaust can contribute to the risk of cancer, cardiovascular diseases, respiratory illnesses such as asthma, and allergies.

Idling is unnecessary in modern cars, but if you do idle there are ways to mitigate the negative effects. Observe the three-minute limit if you are waiting for someone during cold months, then turn the vehicle off for a few minutes and also use a scraper to remove snow or ice from a windshield. Also, do not turn off your engine at stop lights, as that uses more fuel.

A growing number of car and truck models have an auto stop-start function so that when the driver presses the brake pedal, the engine turns off and goes back on when the brake is released. If your vehicle doesn’t have a stop-start function, please honor the three-minute law. By taking these precautions, you will be kind to yourself and others, your vehicle, and the environment. For more, visit CT.gov and search on “anti-idling.”