Truck Chain Laws by State: California, Colorado, Washington and Oregon
Western states require trucks to carry chains in winter and to put them on when signs say so. Each state has its own levels, dates, alternatives and fines.
Truck chain laws require commercial vehicles to carry tire chains on mountain routes in winter and install them when controls are posted. California uses levels R1 to R3. Colorado requires trucks over 16,000 lb to carry chains on about 1,400 miles of highway from September 1 to May 31; Washington requires it on listed passes from November 1 to April 1.
How do chain laws compare by state?
The table summarizes the main commercial vehicle rules as of November 2026. Rules and fines change, and the state DOT’s live road conditions decide what applies on a given day.
| State | Who must carry chains | When chains go on | Notes |
|---|---|---|---|
| California | Heavy trucks must show chains at screening points when Caltrans sets them up | When R1, R2 or R3 controls are posted | Chains on a drive axle; one axle on trailers with brakes |
| Colorado | Commercial vehicles over 16,000 lb combined weight, and vehicles for 16 or more people, on covered highways Sept. 1 to May 31 | When the commercial vehicle chain law is activated | Must-carry law (SB24-100) covers about 1,400 miles; approved alternative traction devices allowed |
| Washington | Vehicles over 10,000 lb GVW on listed routes, Nov. 1 to Apr. 1, regardless of conditions | When chain requirements are posted | At least two extra chains; carry only when posted Apr. 2 to Oct. 31 |
| Oregon | Commercial vehicles over 10,000 lb GVW when conditions may require chains or snow zone signs are posted | When chain signs apply to the vehicle type | Single-drive-axle vehicles over 10,000 lb and vehicles towing are often named on signs |
| Nevada | Check NDOT postings | When chain requirements are in place | Vehicles over 10,000 lb chain drive wheels and braking wheels of the trailer |
| Idaho | Check ITD postings | When ITD posts chain requirements on passes such as Lookout and Fourth of July (I-90) and Lolo (US-12) | Event-based, not a standing season |
What do California’s R1, R2 and R3 chain controls mean?
California posts chain controls in three levels, and trucks towing trailers need chains under all of them:
- R1: chains required on most vehicles. All vehicles towing trailers must have chains on one drive axle.
- R2: chains or traction devices on all vehicles except four-wheel or all-wheel drive vehicles with snow-tread tires on all four wheels.
- R3: chains or traction devices on all vehicles, no exceptions.
For trucks, Caltrans truck chain requirements say chains go on the drive axle and at least one trailer axle must be chained if the trailer has brakes. During unsettled weather Caltrans may set up truck screening, where heavy trucks must stop and show they carry the required chains; trucks without them are turned back to lower elevations. Automatic traction devices are legal and count one-for-one, but trucks using them may be told to add chains on outside wheels. The speed limit under chain controls is 25 or 30 mph.
What is Colorado’s chain law for trucks?
Colorado’s Must Carry law, Senate Bill 24-100, requires commercial vehicles over 16,000 lb used in commerce, and vehicles carrying 16 or more people, to carry chains or approved alternative traction devices from September 1 to May 31 on more than 1,400 centerline miles of highway. CDOT’s map includes sections of I-70, Colorado 9, and US 40, 50, 160, 285 and 550. The CDOT announcement lists a $500 fine for not carrying chains and up to $1,000 plus surcharge for blocking the roadway.
When the commercial vehicle chain law is activated, CDOT uses two levels. At the first, single-drive-axle combination vehicles must chain all four drive wheels, and cables are not allowed as an alternative. At the second, all commercial vehicles must chain up. Chain-up and chain-down stations are signed along I-70 and other corridors. Failing to chain up when the law is in effect also brings a fine, and the amount plus surcharge is printed on CDOT and State Patrol materials.
What are Washington’s and Oregon’s chain rules?
In Washington, vehicles over 10,000 lb GVW must carry at least two extra chains on designated routes from November 1 to April 1, whether or not chain signs are up. WSDOT’s list has included I-90 from North Bend to Ellensburg, I-82 from Ellensburg to Selah, parts of US 97 and US 2, among others; check the current list on WSDOT’s page for chain requirements for vehicles over 10,000 pounds. From April 2 to October 31, chains are required only when posted. Local deliveries that stay outside chain areas and cross no pass are exempt from carrying.
In Oregon, commercial vehicles over 10,000 lb GVW must carry chains when conditions may require them or when snow zone signs are posted. Chain signs often name vehicles towing or single-drive-axle vehicles over 10,000 lb, and ODOT warns that fines for ignoring them run to several hundred dollars.
How do chain laws interact with hours of service?
Time spent chaining up is on-duty time. If snow or a chain control that could not have been known at dispatch slows the trip, the adverse driving conditions exception in 49 CFR 395.1(b) allows up to 2 extra hours of driving to finish the run or reach a safe place, as explained in hours of service rules. It does not cover weather that was already forecast when the load was dispatched. Check chains, binders and tensioners before each mountain trip, and plan where to wait out a closure, since truck parking near passes fills quickly.
Bottom line
Colorado and Washington enforce carrying chains as a seasonal rule, so a truck can be cited on a clear day in October if it has none. California and Oregon focus on what is posted at the time. Carry a full set for your heaviest axle configuration and practice chaining up before the first storm.
FAQ
Are AutoSocks legal for trucks?
California allows automatic and other approved traction devices but may require chains on outside wheels. Colorado allows approved alternative traction devices but bans cables at its first commercial level. Check each state’s list of approved devices.
What is the fine for not carrying chains in Colorado?
CDOT lists $500 for commercial vehicles that do not carry chains on covered highways from September 1 to May 31. Blocking the roadway can cost up to $1,000 plus surcharge.
Do I need chains on every drive axle?
It depends on the state and level. California requires chains on a drive axle and on one trailer axle with brakes; Colorado’s first level requires all four drive wheels on single-drive-axle combinations.
When is Washington’s chain season?
Vehicles over 10,000 lb GVW must carry chains on listed routes from November 1 through April 1, regardless of road conditions.
