Are Snow Socks Legal Where Chains Are Required?
3 lessons in this series, 10 min in total
- Snow Socks vs Snow Chains: Which Do You Need? 3 min read
- Are Snow Socks Legal Where Chains Are Required? 4 min read
- How Long Do Snow Socks Last, and How Fast Can You Drive? 3 min read
This lesson draws on official pages from the California Highway Patrol (CHP), Caltrans, the Colorado DOT, the French government and British Columbia, plus AutoSock’s FAQ. How we research explains the method.
California: textile devices can count
California law speaks of “tire traction devices” (Vehicle Code Section 605), not just steel chains. A May 2024 CHP information bulletin says these can include devices made from textile or plastic, which state regulations call alternative traction devices. To qualify, they must meet or exceed the standards for tire chains or cables, comply with Önorm V5117, V5119 or V5121, and be marked, packaging included, with the standard they meet.
The CHP neither endorses nor recommends any design or style of device, and Caltrans doesn’t recommend brands. So the practical check is the standard marked on the socks or their bag, not the brand name. Without a compliant device, the bulletin says a vehicle can be kept out of a chain control area, and officers may require a specific type of device in severe conditions.
The three California chain control levels
Caltrans posts one of three requirement levels:
| Level | What Caltrans requires |
|---|---|
| R-1 | Chains on all vehicles except cars and light trucks under 6,000 pounds (2,722 kg) gross weight with snow tires on at least two drive wheels; those must still carry chains |
| R-2 | Chains or traction devices on all vehicles except 4WD/AWD with snow-tread tires on all four wheels |
| R-3 | Chains or traction devices on all vehicles, no exceptions |
Under R-2, Caltrans adds that four-wheel and all-wheel drive vehicles must still carry traction devices in chain control areas. Caltrans counts tires marked M+S or MUD AND SNOW as snow-tread tires. The speed limit with chains required is 25 or 30 mph (40 or 48 km/h), and the posted signs and officers’ instructions override any other guide, including this one.
Colorado: AutoSock is on the approved list
Colorado’s DOT runs two laws. Under the Traction Law, passenger vehicles need tires with at least 3/16 in (4.8 mm) of tread that are winter, all-weather or M+S rated, or must carry chains or an approved alternative traction device. Under the Chain Law, the last step before a highway closes, every vehicle needs chains or an approved alternative traction device.
CDOT’s table of approved alternative traction devices lists AutoSock (McGee Company) under both its cable chain and chain types, along with ISSE Tire Sock and two other products. The page says these laws can be enforced with fines on I-70 from Morrison to Dotsero between September 1 and May 31, or when conditions require, and that CDOT can put either law in effect on any state highway.
France, the EU standard and British Columbia
In France, the government’s winter rules apply from November 1 to March 31 in listed towns of 34 mountain departments. Drivers need four winter tires marked 3PMSF, or must carry chains or snow socks for at least two drive wheels. The affected towns are set by prefecture order and marked by road signs.
AutoSock says it was the first snow sock tested and approved to the European standard EN 16662-1:2020, but each country decides which standards it accepts. The California bulletin, for example, names only the three Önorm standards.
British Columbia’s rules center on winter tires, with at least 3.5 mm (0.14 in) of tread and an M+S or mountain-snowflake mark. The province says passenger vehicles may use alternative traction devices with their winter tires, not instead of them: chains on summer tires don’t replace legal winter tires on signed highways. It describes a textile sheath over a winter tire as improving traction like steel chains, working best on snow and ice and wearing quickly on asphalt.
Before you rely on socks
Check three things before a trip: the current rule for your route on the official state or national site, the standard marked on your socks or their bag, and your owner’s manual. The CHP bulletin notes that worn or damaged markings don’t make a device noncompliant, and that no proof of test data is required at the roadside. AWD alone doesn’t excuse you from carrying devices in California; see front or rear wheels for where they go.
AutoSock HP snow socks
Textile snow socks for occasional snow and ice, sold by tire size: pick the size for your tire with AutoSock's size finder. Colorado DOT lists AutoSock as an approved alternative traction device.
Key specs
- Max 30 mph (50 km/h) per AutoSock
- Wear limit: half the white fabric gone
- On Colorado DOT's approved traction device list
- Usable with ABS and traction control on, per AutoSock
Paid link
View on Amazon (opens in a new tab)AutoSock sells its socks by tire size, so pick the size for your tire. If you drive passes often, compare snow socks vs snow chains first.
Sources
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- California Highway Patrol: Tire traction devices information bulletin, May 2024 (PDF)
- Caltrans: Chain controls and chain installation
- Colorado DOT: Passenger vehicle traction and chain laws
- French Ministries of Ecological Transition and Transport: Winter driving, good habits before you leave
- Province of British Columbia: Passenger vehicle tire and chain requirements
- AutoSock UK: Frequently asked questions
