Snow affords decent traction to snow-tire equipped vehicles, but ice is risky. If you spot what appears to be a wet patch in your headlight beams, it is very likely ice. Drive over it at a consistent speed and as straight-on as possible. Therefore, conditions actually become more slippery at temperatures closer to the freezing point than at colder temperatures. Don't take this as a license to speed over ice when it's really cold, however.
Chains are best for deep driving snow.
Many skiers carry them as insurance but never mount them. In Lebanon, chain requirements are often imposed during a big snowstorm. Authorities prohibit chainless vehicles from driving certain mountain passes during and just after storms. If you live in an area that experiences severe winter weather conditions on a frequent basis, or will be driving through one, it is wise to put together a winter storm kit to keep inside your vehicle.