Chain controls can change before the summit

Check the exact highway, direction, and road section before leaving. Check again near the climb. Carry traction devices that fit the vehicle. Practice the maker’s steps for putting them on.

Four-wheel drive, all-wheel drive, and snow tires do not always allow entry. The same is true if the vehicle maker warns against normal chains. You still need a lawful device that fits. Turn back if the vehicle cannot meet the rule.

Caltrans lists three common control levels. Under R-1, most vehicles need chains. Passenger vehicles and light-duty trucks under 6,000 pounds are excepted if they have snow tires on at least two drive wheels. Those vehicles must still carry chains.

Under R-2, most vehicles need chains. A four-wheel-drive vehicle under 6,500 pounds is excepted if it has snow tires on all four wheels. It must still carry chains. Under R-3, every vehicle must put on chains. There is no exception. Rules for towing and heavy vehicles are stricter.

R-1, R-2, and R-3 are agency shorthand. Local areas may vary. Follow posted signs and directions from Caltrans or CHP. Do that even if an app, radio report, or old screenshot says something else. Controls can tighten fast. A closure means the road is closed to travel.