For most folks who drive in winter weather, the idea of buying winter tires has at least crossed their minds. It just makes sense, because any small advantage in traction can make a big difference on treacherous roads. That’s important, considering some 95,000 people are injured each year in auto accidents caused by snow, sleet and ice.

On the other hand, winter tires aren’t exactly cheap. Customers can expect to pay more than $140 per tire with a popular SUV, such as the 2018 Subaru Forester. Then there’s the fact that the Forester, along with most of the SUVs and pickups sold today, has all-wheel drive. So do quite a few cars. Many people think that ordering a vehicle with that hardware is all they need to handle snow and ice.

The experts don’t agree. The cold, hard facts indicate that if you want optimum traction in wicked weather, you need winter tires.

Let’s find out why.

What’s the Difference between Winter Tires and Regular Tires?

There are two key differences between winter tires and so-called “regular” tires. For starters, they’re made out of different rubber compounds. The material used for winter tires is specifically engineered to stay relatively soft when the weather turns cold. That softness allows the tires to grab onto the rough surface of the road, creating traction. Indeed, winter tires are so soft that they often can get some grip even if there’s ice on the road.

Also helping matters are the specially tailored tread patterns for winter tires. They have a variety of extra cuts, grooves and channels, all with separate jobs. For example, some “bite” into slippery surfaces for extra grip. Others direct melting water away from between the tires and the road. This can reduce the chances of hydroplaning.

When it comes to the demands of summer driving, winter tires are too soft. Those complicated tread patterns can quickly wear down in the higher temperatures.

As a result, most new vehicles try to provide the best of both worlds with all-season tires. Like their name tells you, all-season tires are designed for year-round driving. This means they should be soft enough to create traction in the cold, but hard enough to stand up to the heat of summer driving. In the real world, however, all-season tires lose enough flexibility in colder weather to start losing their grip. Nor do they have the fancy tread designs for managing the snow, slush and other precipitation.

Do You Need Winter Tires with All-wheel Drive?

Let’s be clear. An all-wheel-drive system can be a major benefit if you want to avoid getting stuck in the snow. By providing engine power to all four wheels, it can ensure there’s twice the opportunity for traction as with a two-wheel-drive vehicle. Additionally, many systems can adjust power distribution so that the wheels with the most grip get the most power. Yet once you’re underway, all-wheel drive won’t help you stop any faster. And even advanced all-wheel-drive technology has only a marginal effect on cornering in slippery conditions.

What Do the Numbers Show?

To see exactly how much performance can vary between winter tires and their all-season counterparts, consider the research. Consumer Reports recently tested an all-wheel-drive 2015 Honda CR-V for braking performance in the snow. With that compact SUV traveling at 60 mph and wearing winter tires, it took 310 feet before coming to a stop. With all-season rubber, the distance was more than twice as long, at 668 feet.

It’s further worth noting that off-road tires are no substitute for winter ones. The FourWheeler network discovered that in its own real-world evaluations. Here, the test truck was a 2016 Ford F-150 with four-wheel drive. Running on a closed, snow-covered track, the FourWheeler team put the truck through its paces with all-season, mud, all-terrain, winter and studded winter tires. Unstudded winter tires delivered the best performance, including stopping distances half as long as with mud tires.

In terms of “average trends,” Consumer Reports data also shows that winter tires enable 20 percent shorter stopping distances than all-season tires. The winter tires had a traction advantage in the snow as well. They allowed cars to travel 34 percent farther than all-season tires while accelerating from 5 to 20 mph.

When Do I Need Winter Tires?

A general rule is that winter-rated tires work best for customers who do extended amounts of driving in temperatures below 45 degrees.