Chain control checker
Over Donner, Echo or any Sierra pass, the question at the chain checkpoint is not whether you have four-wheel drive — it is which requirement is posted and what tires you are on. Answer four questions to see what Caltrans' rules mean for your car.
Your car and the sign
The three levels, in Caltrans' words
- R-1: chains are required on all vehicles except passenger vehicles and light-duty trucks under 6,000 pounds gross weight equipped with snow tires on at least two drive wheels. Vehicles using snow tires must carry chains; vehicles towing trailers must have chains on one drive axle, and trailers with brakes on at least one axle.
- R-2: chains or traction devices are required on all vehicles except four-wheel/all-wheel drive vehicles with snow-tread tires on all four wheels, which must carry traction devices.
- R-3: chains or traction devices are required on all vehicles, no exceptions. Caltrans notes R-1 and R-2 are the most common, and a highway will often be closed before R-3 is imposed.
Source: Caltrans chain controls.
Before the trip: the insurance side
Whether your policy pays to repair your own car after a winter slide depends on the coverage you carry — check your declarations page for collision and comprehensive before you go, and keep your proof of insurance and your insurer's claims number on your phone. Mountain passes are also where you are most likely to need towing, so it is worth knowing whether you carry roadside coverage and what its limits are; that varies by company.
Sources (official)
Posted signs and instructions from Caltrans or CHP at the checkpoint always control, even when they differ from this page or a road report. Check Caltrans QuickMap before you leave.
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What does R-1 mean in California chain controls?
Chains are required on all vehicles except passenger vehicles and light-duty trucks under 6,000 pounds gross weight with snow tires on at least two drive wheels; those vehicles must still carry chains. Vehicles towing trailers must have chains on one drive axle (Caltrans).
Does 4-wheel drive mean I don't need chains?
Only under R-1 or R-2 with the right tires. Under R-2, four-wheel and all-wheel drive vehicles are exempt only with snow-tread tires on all four wheels, and must carry traction devices. Under R-3, every vehicle needs chains or traction devices (Caltrans).
Can I get a ticket for not putting on chains?
Yes. Caltrans says you must stop and put on chains when signs require them, and the California Highway Patrol can cite and fine you if you don't.
Is R-3 common?
Caltrans says R-1 and R-2 are the most common conditions, and a highway will often be closed before R-3 is imposed.