Get a grip. To have adequate snow traction, a tire requires at least 6/32-inch deep tread, according to The Tire Rack. (New passenger-car tires usually have 10/32-inch of tread.) Ultrahigh-performance "summer" tires have little or no grip in snow. Even "all-season" tires don't necessarily have great snow traction: Some do, some don't. If you live where the roads are regularly covered with snow, use snow tires (sometimes called "winter tires" by tire makers). They have a "snowflake on the mountain" symbol on the sidewall, meaning they meet a tire-industry standard for snow traction. More.