The most important safety items on your vehicle, above all others, are your tires. And that’s especially important in winter, when they have to deal with a wide variety of surfaces, including snow, slush and ice.

Winter tires do a far better job than all-season tires, even on dry pavement: once the temperature drops below 7C, their more pliable rubber compound and aggressive tread do a better job of gripping the road.

I experienced the worst of winter driving at an event showcasing the new Michelin X-Ice Xi3 winter tire, which goes on sale next fall. I drove on several surfaces with brand-new Xi3 tires, but perhaps the most eye-opening was when the company sent me out on worn ones. As your tires wear, you need to be aware of how they’re changing and adjust your driving habits if necessary.

Tire treads consist of “blocks,” squares of rubber that bite into snow; grooves and channels that evacuate water; and sipes, tiny slits in the blocks that improve traction. As the tires wear, the blocks will become smooth and the channels will become shallower, making it harder for the tire to grip the surface and displace water.

This can potentially lead to a dangerous situation called hydroplaning, where the tire “floats” on top of puddles and slush, rather than pushing water aside so it can contact the asphalt.

The Xi3′s special design helps to give it even tread wear as it ages, but many tires will wear unevenly, especially if they’re running with the wrong air pressure. This will gradually affect how they handle.

On an ice and snow course, driving on four brands of tires all worn to the same degree, I quickly noticed the difference.

One had difficulty getting traction on an incline, while another had lost much of its lateral stability: on sharp curves, it tended to slip sideways.

Most importantly, while some were better than others, none of them stopped as quickly as a car with newer tires. No matter what type of tires or the season, you should be regularly analyzing how your car behaves. Any time you realize that your driving is overly compensating for your tires, it’s time to have them checked, and if necessary, replaced.

Every time you leave your driveway, your safety, your family’s safety, and that of other drivers starts with the condition of your tires.