Western mountain passes — RV chain and traction rules by state

Seven states, in their own words

Weight, towing and the calendar move the line: 10,000 pounds in Oregon and Washington, 26,001 in Montana's carry rule; chains on a braked trailer's axle in Oregon; November 1 to March 31 in Washington, October 1 to April 30 in Montana. Open a state for its own sentences and source.

Nevada and Idaho are not in this table yet: check the Nevada DOT and Idaho 511 pages before a winter crossing.

• California: chains on the drive wheels when signs say so; 25 or 30 mph when chains are required

  “You must stop and put on chains when highway signs indicate chains are required.”

  “You can be cited by the California Highway Patrol and fined if you don't.”

  “Chains must be installed on the drive wheels.”

  “The speed limit when chains are required is 25 or 30 miles an hour.”

  From Caltrans's page, read September 25, 2026.

• Oregon: RVs over 10,000 and under 26,001 lb are medium duty; when signs require chains, a braked trailer takes them on one axle

  “Vehicles with a GVW rating of more than 10,000 pounds but less than 26,001 pounds such as buses, RVs, and cargo vehicles.”

  “Single-drive axle medium duty vehicles must have chains on one tire on each side of the drive axle.”

  “In typical winter conditions, vehicles rated at 10,000 pounds gross vehicle weight (GVW) or less and not towing or being towed are allowed to use traction tires in place of chains.”

  “When towing, chains must also be on one tire on each side of one axle of a trailer that is equipped with a brake.”

  “Drivers who disobey the signs requiring chains or traction tires are subject to a class C traffic infraction.”

  From ODOT's page, read September 25, 2026.

• Washington: over 10,000 lb, carry chains over any pass Nov. 1–March 31, posted or not

  “Any vehicle over 10,000 pounds gross vehicle weight (this can include large SUVs) is required to carry a minimum of two chains (or one set of tire chains) over any Washington mountain pass from Nov. 1 to March 31 – even if a chain up requirement is not posted.”

  “Studded tires do not meet state chain requirements.”

  “A chain alternative must be on the approved WSP list to qualify as meeting the chain requirement.”

  From WSDOT's page, read September 25, 2026.

• Utah: traction devices where the law requires them in severe winter weather

  “During severe winter weather, drivers must use traction devices where required by law.”

  “This PDF summarizes the traction law for state highways in Utah, and has a map showing the affected routes.”

  From UDOT's page, read September 25, 2026.

• Colorado: while CDOT has the passenger vehicle chain law in effect, every vehicle needs chains or an approved device; fines from $100

  “CDOT can implement traction and chain laws on any state highway.”

  “When the passenger vehicle chain law is in effect, every vehicle must have chains or an approved alternative traction device.”

  “The penalty for failing non-compliance includes a $100 fine and $33 surcharge.”

  “Failing to comply with restrictions that resulted in a road closure of a travel lane in one or more directions can include a $500 fine and a $157 surcharge.”

  From CDOT's page, read September 25, 2026.

• Wyoming: two restriction levels; don't stop in the driving lane to chain up

  “Wyoming’s chain law includes two levels of restrictions that can be implemented on specific highway sections when conditions warrant.”

  “When conditions are extremely hazardous, travel can be restricted to: Vehicles equipped with tire chains; or All-wheel-drive vehicles equipped with adequate mud and snow or all-weather-rated tires.”

  “Do not stop in the driving lane to install or remove chains!”

  From WYDOT's page, read September 25, 2026.

• Montana: when MDT requires chains, towing units chain one drive axle; Oct. 1–April 30, towing units of 26,001 GVW or more carry them

  “The Department of Transportation may determine at any time (year-round) that dangerous or unsafe conditions on a highway require tire chains in designated areas where tire chains may be required.”

  “When the Department of Transportation determines tire chains or traction equipment are required, all vehicles towing a trailer (towing units) must apply chains to the driver wheels of one axle.”

  “Between October 1 and April 30 of the following year, towing units 26,001 GVW or greater must carry tire chains or an approved traction device when traveling in an area where tire chains may be required. Note: This does not apply to a vehicle with four-wheel drive.”

  From MDT's page, read September 25, 2026.