The difference between regular radial tires and snow tires is in the construction. Snow tires are better able to handle weather extremes, such as ice and cold. Even though regular tires have come an awful long way from the old bias-ply tire, the snow tire has the extra "oomph'" for the stronger traction that is necessary in the snow and ice.
Driving in wintry conditions, the most important factor a tire needs to accomplish is holding the road! We all know how difficult it is to drive on ice, and the slippery conditions not only make car handling tough, but dangerous as well. Then there is something called "black ice". This is when a layer of frozen water which is almost invisible builds up on the road, and it is extremely dangerous! If you live in parts of the country where conditions such as this exist, it's advisable to invest in a set of snow tires.
So what is the main difference between regular tires and snow tires? Snow tires are manufactured to handle extreme cold and keep the tire pliable enough to handle it. Studs can be incorporated into the design of the tire as well to give extra traction. It's the next best thing to putting chains on the vehicle. Speaking of chains, there are some parts of the country, specifically I-80 between the California border and Nevada where chains are not only advisable, they are mandatory! Winter brings some severe snow and ice conditions on this road, and I've personally seen snow drifts as high as twenty feet! It also crosses the Sierra Nevada mountain range with high altitudes, all of the ingredients that make winter driving very, very hazardous.
All season radials do a good job when conditions change, but when Old Man Winter blows his top, then snow tires are a must. Regular tires can give a quieter ride than snow tires due to the angle of the tread design, but snow tires will give the extra traction necessary to handle patches of ice that crop up on the roads. When driving in these conditions, be extra cautious when driving through the bridge underpass, and the overpass for that matter! Ice tends to accumulate faster in the underpass, as more moisture exists and the sun doesn't get a chance to melt it.
Driving is already a dangerous enough activity, so get the odds on your side. If you live in sections of the country that experience serious winter weather conditions, it just makes sense to invest in a set of snow tires. You've got a big investment to protect, and the biggest one could be your life!