MileCheckDo you need chains or are all-season tires enough?
Carry compatible chains or an approved alternative when planning a winter pass trip. All-season tires do not give you a blanket exemption. The posted restriction, vehicle and tire markings decide what you must fit.
Facts checked September 2026. Every number links to its source; prices and rules change, so confirm the day you travel.
California has three chain levels
For passenger cars without trailers, R1 allows a snow-tire exception for qualifying vehicles under 6,000 pounds. R2 exempts AWD or 4WD with snow-tread tires on all four wheels. Both exceptions still require carrying chains. R3 requires chains on every vehicle.
Follow the posted control and instructions at the checkpoint.
Washington and Oregon have conditional exceptions
Washington’s usual AWD exception applies below 10,000 pounds GVWR with all wheels engaged, approved traction tires and chains carried for a drive axle. An all-vehicles chain restriction removes that exception.
Oregon’s lighter-vehicle traction-tire and four-wheel-drive exceptions have conditions. A conditional closure can require chains even on those vehicles. Check the full rule if towing.
Washington State Patrol traction rules · Oregon chain law.
Colorado’s current rule is stricter than older summaries
CDOT’s fall-2025 update lists AWD or 4WD with qualifying tires and at least 3/16-inch tread, or chains or an approved alternative. Do not assume a two-wheel-drive car with winter tires alone qualifies.
The Passenger Vehicle Chain Law requires every vehicle to use chains or an approved device. Check conditions on I-70 before leaving.
CDOT passenger-vehicle traction law.
Read the sidewall
M+S and the three-peak mountain snowflake are different markings. Oregon identifies the mountain-snowflake symbol with severe-snow standards. California’s snow-tread definition can include M+S.
“All-season” on a sales receipt does not answer the legal question. Read the tire’s markings and check its tread against the state’s rule.
ODOT traction tires · Caltrans chain controls.
Fit them before the trip
Use your vehicle manual to choose a compatible device and axle. Practise fitting it in dry weather. Stop in a designated, level chain-up area outside the travel lane.
If your vehicle cannot take conventional chains, confirm an approved alternative before leaving. Read what chain restrictions mean and check the pass report again before climbing.
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Questions, answered
Does AWD mean you can leave the chains home?
No. An exemption from fitting chains can still require carrying them.
Do studded tires replace chains?
Not under Washington’s chain requirement.
Does California R3 exempt winter tires?
No. R3 requires chains on every vehicle.
Are two-wheel drive and winter tires enough in Colorado?
Do not rely on that. CDOT’s current passenger traction options require chains or an approved device for two-wheel-drive vehicles.
Can you use any tire sock?
Check both state approval and compatibility with your vehicle.
Do chains guarantee that the pass stays open?
No. Obey closures and current restrictions.
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