In extreme climates, snow tires have been designed to replace the standard radial tires for the winter season to make driving on snow and ice safer. These special tires have deeper treads that increase traction and a type of rubber that maintains its resilience in cold temperature. They are rated to better handle slippery road conditions like sleet, mud, ice, or flooding.
Even though standard tires that come with a car are often called "all-season," they're not ideal for extensive driving over many months of consistent snowfall or slush, but rather sporadic storms or the odd ski trip. Therefore, many safety boards recommend people living in extreme climates to invest in four snow tires and install them for the winter. Regardless of whether a car has front or rear drive, drivers should use four tires of the same brand that are marked M/S, which stands for mud and snow, and an icon of a snowflake within a mountain.
The reason these tires stick to the road and make for safer driving is their tread and material. In the US, the Rubber Manufacturer's Association will designate snow tires M/S only if they fulfill the requirements of the depth and pattern on their tread, which means the tires have the proper grooves to fling off snow and connect to the pavement. They're also made of a slightly different rubber compound that doesn't stiffen at low temperatures and therefore more evenly distributes the weight of the car on the tires. Of course, driving in hazardous conditions makes it even more important that the tires are always properly inflated so they have the correct footprint, the area where the tire touches the road, for maximum traction.
The increased friction of properly installed snow tires can keep a car on the road, maintain normal steering, and allow the driver to safely navigate in the dark or at higher speeds. These tires reduce the probability that the wheels will spin when the driver applies the brakes. They can also prevent the car from hydroplaning, which happens when there is an even layer of water on the road and the tires slide over it rather than make a path through it. Studded snow tires combine elements of snow chains without the bulk or damage to the asphalt. These specialty tires have small metal studs embedded in the rubber for a stronger grip, but they are not necessary or favorable for all roads.