I have a 4-wheel drive vehicle. Do I have to carry / use chains? What do the "R" ratings which are associated with chain requirements mean?
"R" ratings on snowy roads indicate chain requirements for various conditions.
Some vehicles may not be required to use chains under all conditions, but all vehicles must carry chains. Most vehicles come equipped with snow tires. Look for M+S (mud and snow), All Season, or All Terrain, on the side of the tire.
R-1 chains required except for vehicles with snow tires (chains required for any vehicle pulling a trailer)
R-2 chains required except for 4-wheel drive with snow tires
R-3 chains required for all vehicles