R-2: Chains are required on all vehicles except four-wheel drives with 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.
SR 89 BETWEEN McCLOUD AND MT. SHASTA
SR 44 IN SHINGLETOWN
R-1: Chains are required on all commercial vehicles (trucks or buses). All other vehicles (cars, pick-ups, vans, etc.) must have either snow tread tires or chains on the drive axle.
INTERSTATE 5 AT GIBSON
SR 36 AT AND EAST OF SR 3
SR 36 TO SR 89 BETWEEN MINERAL AND CHESTER
R-1M: Chains are required on single-axle drive vehicles with trailers (commonly referred to as R1 Modified).
SR 36 JUST WEST OF SR 3 NEAR FOREST GLEN
-from press release