There is more to winter driving than turning on the heater full blast, buckling up and stepping on the gas. According to a 15-minute instructional video out of Wyoming, the most important winter driving factor is your choice of tires. People from warm climates often come to the inland West with wide tires, which guarantee a snowboard effect on snow. Instead, get the narrowest tires your car can safely use. Once you have proper tires, don't start up without knowing whether you have conventional brakes, which you pump when you're on thin, or thick, ice, or ABS brakes, to which you apply steady pressure. And don't put faith in four-wheel-drive vehicles. They lock up and skid as easily as conventional cars. All this and more is from Driving Snow: The Keys to Winter Driving, produced by Sava Malachowski and directed by Jim Elder. For a copy, send $14.95 to SavaFilm, P.O. Box 836, Wilson, WY 83014 (307/739-2256).