California State Law, encated in 1991, requires that all vehicles must carry tire chains/cables at all times when
entering a chain control area, such as Yosemite National Park. This requirement is in effect from November 1st to April
1st, though the requirement can be extended based on weather. Failure to comply with this law leaves you vulnerable to
fines and charges for any damage done should you have an accident. Additionally, your car may be towed if a law
enforcement officer stops you and you do not have chains in your possession. Weather conditions can change quickly in
the mountains causing chains to become necessary immediately when traveling at higher elevations.
Below, you will find definitions for the four 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 or cables are required on all vehicles -except passenger vehicles and light duty trucks
under 6,000 pounds gross weight that are equipped with snow tires on at least two drive wheels. Vehicles using snow
tires must carry chains or cables. All vehicles towing trailers must have chains or cables on one drive axle. Trailers
with brakes must have chains or cables on at least one axle.
R-2: Chains or cables are required on all vehicles -except four-wheel drive vehicles under 6,500
pounds gross weight which are equipped with snow tires on all four wheels. Four wheel drive vehicles using snow tires
must carry chains or cables for one set of drive wheels.
R-3: Chains or cables are required on all vehicles without exception.
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.