If you can't remember the last time you checked your tires, you're overdue. Tires lose pressure when the weather gets colder, about a pound per square inch for every 10-degree drop.

"If you haven't checked your tire pressure since the warm weather, your tires could be underinflated by five or more pounds per square inch." said Consumer Reports' Jon Linkov.

In Consumer Reports' emergency handling test, drivers with underinflated tires had trouble. But once the tires were properly inflated, the drivers had no problems.

And underinflated tires cost you more money. They wear out sooner. And they hurt your gas mileage.

So how often should you check your tires? At least once a month.

It can be confusion to figure out how much air pressure your tires need. Don't go by the number listed on the sidewall, that's the maximum inflation pressure. The correct pressure is listed in your owner's manual, or you can find it on the doorjamb or inside the glove box lid. You can find more tips on tire maintenance free at www.ConsumerReports.org.