When winter conditions exist in Yosemite, the
park service requires all visitors to carry chains in their vehicle at all times, even if the vehicle is equipped with 4-wheel drive. Rangers evaluate the road conditions and determine the chain control levels.
Below, you will find definitions for four of the levels within a chain control area.
R-0: No restrictions, however all vehicles are required to carry chains or cables at all times.
R-1:Chains are required on all commercial vehicles (trucks or buses). All other vehicles (cars, pick-ups, vans, etc.) must have either mud and snow tread tires or chains on the drive axle.
R-2: Chains are required on all vehicles except four-wheel drives with mud and snow tread tires on all four wheels and provided that tire traction devices for at least one set of drive wheels are carried in or upon the vehicle.
R-3: Chains required - ALL VEHICLES- no exceptions
CalTrans has more information on chain controls and highway conditions outside Yosmite National Park.
Additional Information:
- Mud and Snow tires are typically designated with a "M+S" on the side of the tire, and must have a minimum tread depth of 6/32 of an inch to be legal.
- Tire traction devices (chains) can be link chain, cable chains and/or spider straps
- Studded snow tires may be used if the tires are also rated as snow tires, if not, the tires must be chained up as Studs do not replace chains.
- Any vehicle with a gross vehicle weight of 10,000 pounds must chain up. (Typically this applies to large vans and up.)
- All vehicles, including those with 4-wheel drive with snow tires that are towing trailers must have chains on one drive axle of the vehicle
- If the trailer has brakes, it must also have chains on one axle.
