Warming up the car before hitting the road is a pervasive winter ritual, but it's a pointless exercise for most modern vehicles, the Washington Post reports. What's more, a 2009 study found that idling of all types accounts for 1.6% of the country's greenhouse gas emissions—worse for the environment than the iron and steel manufacturing industry. We're also wasting tons of money—an experiment in frosty Canada idled three cars at varying times after subjecting them to a deep freeze. They found fuel consumption jumped up as much as 14% with a five-minute idle, and up to 19% with a 10-minute idle. If drivers just hopped in their cars without the average five-minute warm-up, they'd save $5.9 billion a year in fuel—and that's based on 2008 prices.
So why do we do it? Apparently, old habits: Auto experts say older models with carburetors actually do need to warm up before driving, and a car's fuel economy does suffer in cold weather. But newer cars don't need to be primed—they have electronic fuel injection, which monitors temperature and makes the warm-up unnecessary. Auto experts say 30 seconds is all new cars need. "The engine will warm up faster being driven," the EPA and Department of Energy explain. Idling cars have become a matter for lawmakers in some states and cities, and some vehicles now use start-stop technology to lessen idling in traffic. (Beavers are also kinda bad for the environment.)