In short. Chain laws in the western United States are switched on by roadside signs, not by the calendar, and each state has its own levels. In California, R-1 requires chains except on cars and light trucks under 6,000 lb with snow tyres on two drive wheels, R-2 exempts only four-wheel and all-wheel drive vehicles with snow-tread tyres on all four wheels, and R-3 requires chains on every vehicle. Colorado's Traction Law, revised in autumn 2025, applies on I-70 between Morrison and Dotsero from 1 September to 31 May: according to CDOT's 2025 release, 4WD and AWD vehicles need tyres with at least 3/16 inch (4.8 mm) of tread marked M+S, all-weather or mountain-snowflake, and other vehicles need chains or a device from the state's list on two drive tyres. Washington and Oregon accept traction tyres at the lower levels and ask 4WD drivers to carry chains. Everywhere, the chain must also fit around your tyre, which car makers often rule out on large or aftermarket wheels.
How chain laws work in the United States
There is no federal chain law. Each state's transport department posts the requirement on signs at the entry to a controlled area, and the highway patrol enforces it. The level can change within the hour, so the rule that counts is the one on the sign: Caltrans asks you to follow the signs and the staff at checkpoints "even if these are at variance with broadcast road condition reports".
- Chains usually means more than link chains. Oregon's definition covers "link chains, cable chains, or any other device that attaches to the wheel, vehicle or outside of the tire".
- Alternative traction devices (ATD) are cable chains, textile socks and similar products. California accepts them if they meet Vehicle Code section 605; Colorado and Washington keep lists of accepted products.
- Snow or traction tyres carry M+S or the three-peak mountain and snowflake symbol, with a minimum tread that differs by state.
- The 4WD and AWD exemption is always conditional, and never valid at the top level.
The four states side by side
Our own summary of the official pages read on 16 October 2026, for passenger vehicles not towing (a trailer changes the rules everywhere).
| California | Colorado | Washington | Oregon | |
|---|---|---|---|---|
| Levels | R-1, R-2, R-3 | Traction Law, then Passenger Vehicle Chain Law | Traction tires advised, Traction tires required, Tire chains required, Chains required on all vehicles | Carry chains or traction tyres; use chains or traction tyres; conditional closure |
| When | When signs are posted | I-70 Morrison to Dotsero, 1 Sept to 31 May; any state highway when conditions require | When signs are posted | When signs are posted, on any highway |
| Tyres accepted instead of chains | Snow-tread tyres (M+S), 6/32 in minimum, at R-1; with 4WD at R-2 | 3/16 in tread, M+S, all-weather or mountain-snowflake (4WD and AWD) | Traction tyres under WAC 204-24-040, 4/32 in, M+S or mountain/snowflake | Traction tyres (studded, or the mountain/snowflake emblem) up to 10,000 lb GVW |
| 4WD and AWD | Exempt at R-2 with snow-tread tyres on all four wheels; must carry traction devices | Tyre route above; chains at Chain Law level | Exempt at "Tire chains required" if all wheels are in gear on traction tyres and chains are carried | Exempt in typical conditions if six conditions are met, chains carried |
| Top level | R-3: chains on all vehicles, no exceptions | Chain Law: every vehicle needs chains or a device from CDOT's list | Chains required on all vehicles, 4WD included | Conditional closure, for example chains on all vehicles except 4WD not towing |
| Fine as published | Not stated by Caltrans | $100 + $33 surcharge (traction law page); $50 + $17 (release of 20 Nov 2025) | $500 | Class C infraction; $800 for not using chains or traction tyres |
California: R-1, R-2 and R-3
Caltrans describes three levels:
R-1: chains are required on all vehicles except passenger vehicles and light-duty trucks under 6,000 lb (about 2,720 kg) gross weight with snow tyres on at least two drive wheels; in Caltrans' words, "Chains must be carried by vehicles using snow tires."
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." (4WD and AWD vehicles "must carry traction devices in chain control areas".)
R-3: "Chains or traction devices are required on all vehicles, no exceptions."
R-1 and R-2 are the most common. The speed limit with chains is 25 or 30 mph, and the California Highway Patrol can cite you if you drive on without them. Caltrans does not publish the fine.
What counts as a snow tyre. Vehicle Code section 558, quoted by Caltrans, defines a snow-tread tyre as one with "a relatively deep and aggressive tread pattern compared with conventional passenger tread pattern", and Caltrans says it is identified by MS, M/S, M+S or MUD AND SNOW on the sidewall. Its chain requirements sheet, revised in October 2016, sets the minimum tread for those tyres at 6/32 inch, which is 4.8 mm.
What counts as a device. Section 605, also quoted by Caltrans, defines tire traction devices as "devices or mechanisms having a composition and design capable of improving vehicle traction, braking and cornering ability upon snow or ice-covered surfaces", built so they cannot come off by accident and marked with the maker's name. The sheet lists cable chains, textile snow chains, wheel-hub chains and automatic chains as examples, and warns that "less conventional devices" may be restricted at times because of local conditions.
A difference between two Caltrans documents. The web page asks only vehicles on snow tyres (at R-1) and 4WD vehicles (at R-2) to carry chains or devices. The 2016 sheet goes further: "All vehicles, including four-wheel or all-wheel drive vehicles must carry chains upon entering a chain control area." The stricter reading costs only boot space.
Colorado: the Traction Law and the Chain Law
Colorado has two passenger-car levels. CDOT's page: "Morrison to Dotsero on I-70 between Sept. 1 and May 31, or if conditions require, these laws could be enforced with fines." Either law can be activated on any state highway.
The Traction Law as revised in 2025. The Colorado bill SB25-069 was signed on 15 May 2025 and took effect on 6 August 2025. CDOT's news release of 20 November 2025 sums up the result:
"As of this fall, Colorado's updated Traction Law requires tires with a tread depth of at least 3/16-inch that are winter tires (mountain-snowflake icon), all-weather rated tires or mud and snow (M+S) tires. The law applies to all 4WD and AWD vehicles." A vehicle that does not meet these standards needs chains or an accepted alternative traction device (ATD) on two or more drive tyres.
The release says the law now "emphasizes tire condition and type for compliance, regardless of vehicle drivetrain". 3/16 inch is 4.8 mm, as in California. For a two-wheel-drive car, the release lists only chains or an ATD. CDOT's traction law page, read the same day, still says "passenger vehicles" may use the qualifying tyres "or carry chains". We did not read the codified statute (C.R.S. 42-4-106) and cannot settle the point. Our reading: in a two-wheel-drive car, having chains or a listed device ready to fit on the drive tyres satisfies both pages.
The Passenger Vehicle Chain Law is, in CDOT's words, "the final safety measure before the highway is closed". When it is on, every vehicle must have chains or an accepted alternative traction device, whatever the tyres or the drivetrain.
Alternative devices. CDOT's page lists six entries from four makers; check that yours is on it.
Fines. The two CDOT pages disagree. The traction law page gives $100 plus a $33 surcharge, and $500 plus $157 if your non-compliance closes a lane. The release of November 2025 gives $50 plus a $17 surcharge. Both were online on 16 October 2026. The bill also obliges rental companies to tell renters about the chain law; check a rental's tyres against the 3/16 inch anyway.
Washington: four signs
WSDOT's winter driving guide, last modified in January 2025, lists four levels:
| Sign | Passenger vehicles |
|---|---|
| Traction tires advised | Advice only; oversize loads banned |
| Traction tires required | All passenger vehicles need traction tyres as defined by the state; chains on vehicles over 10,000 lb GVWR |
| Tire chains required | All vehicles need chains, except 4WD and AWD, which must still carry them; $500 fine |
| Chains required on all vehicles | All vehicles must fit chains, 4WD and AWD included |
Regulation WAC 204-24-040 defines the traction tyre the State Patrol accepts: at least 4/32 inch of tread (3.2 mm) measured at three points in the centre, an aggressive pattern, and the M+S marking or the mountain/snowflake symbol. The WSDOT guide adds that once accepted chains are fitted, "any tire becomes a traction tire" and that studded tyres "do not meet chain requirements". Studs are unlawful from 1 April to 1 November under RCW 46.37.420.
Under WAC 204-24-050, AWD vehicles are exempt from "chains required" signs when all wheels are in gear and fitted with accepted traction devices, provided chains for one set of drive tyres are carried. Alternative devices on the State Patrol's list are accepted; the WSDOT guide names six for passenger cars.
Oregon: traction tyres up to 10,000 lb
Oregon's chain law "applies to all highways throughout the state", says TripCheck, ODOT's travel site. Vehicles rated at 10,000 lb GVW or less that are not towing may use traction tyres instead of chains. Oregon's definition of a traction tyre is narrower than the other states': studded tyres, retractable-stud tyres, or tyres "marked with a mountain/snowflake emblem". Studs are legal from 1 November to 31 March.
A four-wheel or all-wheel drive passenger vehicle is exempt in typical conditions only if all six conditions hold: unloaded weight of 6,500 lb or less, power to both axles, chains carried, mud and snow, all-weather radial or traction tyres on all wheels, no trailer, and not being driven so that it loses traction. Above that, ODOT may impose a conditional closure; a typical one on I-5 over the Siskiyou Pass reads "Chains required on all vehicles excluding four wheel drive vehicles unless towing", and traction tyres are then not enough.
TripCheck calls a failure to obey the signs a class C traffic infraction. ODOT's Winter Snow Zone page adds that not using chains or traction tyres when signs require them "could result in a specific fine traffic violation with an $800 fine".
Tread depths in one table
The states measure the same thing in different units. The conversion is ours: one thirty-second of an inch is 0.794 mm.
| Jurisdiction | Text | Minimum tread | In mm |
|---|---|---|---|
| California | Caltrans sheet, rev. 10/16 | 6/32 in (M+S tyres) | 4.8 mm |
| Colorado | CDOT, 2025 release | 3/16 in = 6/32 in | 4.8 mm |
| Washington | WAC 204-24-040 | 4/32 in | 3.2 mm |
| British Columbia | Government of BC | 3.5 mm | about 4.4/32 in |
| Oregon | TripCheck | no depth given; type of tyre only | n/a |
A tyre that meets Washington's rule can fail California's and Colorado's. A tread depth gauge settles it before the trip.
Outside the United States
Canada, British Columbia. Signs requiring winter tyres or chains on board apply from 1 October to 30 April, and to 31 March on some highways outside the passes. A legal winter tyre has at least 3.5 mm of tread and the M+S marking or the mountain/snowflake symbol. And: "Chains on summer tires are not an acceptable substitute for legal winter tires on signed B.C. highways." The fine for a passenger vehicle without winter tyres where required is C$121. Dates, studs and Quebec's rules are in our guide to winter tyre laws in Quebec and British Columbia.
Australia. In New South Wales, all two-wheel-drive vehicles must carry chains between the June and October long weekends on three Kosciuszko roads (Kosciuszko Road from the park boundary at Thredbo River, Alpine Way between Thredbo and Tom Groggin, Island Bend/Guthega Road), and fit them when told. Chains are not compulsory for 4WD and AWD vehicles there, but recommended. Transport for NSW warns that some tyre configurations cannot take chains. In Victoria, a motoring club's article says all vehicles must carry chains in the designated alpine areas and only diamond-pattern chains are legal. We could not open the Victorian authorities' own pages, so check them before you go.
United Kingdom and Europe. No British rule asks for chains; for the Alps, see snow chains and snow socks in Europe and winter tyres in the UK.
Will chains fit your wheels?
A chain needs room around the tyre: in front of the tread, and between the inner sidewall and the suspension, brake lines and strut. A chain maker's page recalls the 1980 SAE standard J1232, under which "the minimum clearances specified must be maintained around fenders, braces, suspension parts, strut housings, splash pans and fuel/brake lines", and says most of today's vehicles need class S products. The classes, as an encyclopaedia entry gives them (we did not read the paid SAE text):
| SAE class | Gap at the tread | Gap at the inner sidewall |
|---|---|---|
| S | 37 mm (1.46 in) | 15 mm (0.59 in) |
| U | 50 mm (1.97 in) | 23 mm (0.91 in) |
| W | 64 mm (2.50 in) | 38 mm (1.50 in) |
The entry notes that class S is common on newer cars, "especially if after-market wider, low-profile, or larger tires and/or wheels are fitted". Two car makers show how narrow the handbook limits can be. Porsche's instructions for its own snow chain set for the Macan (95B), dated 24 November 2020 and published by NHTSA, say the chains must not be used on the front axle, nor "with 20-inch and/or 21-inch winter and all-weather tires". Polestar's 2024 manual for the Polestar 2 advises against chains on wheels larger than 20 inches, allows them on the rear wheels only (all-wheel drive included), and says they must not be used "if accessory, aftermarket or 'special' tyres and wheels are fitted that have a different size to the original". Both set 50 km/h (30 mph) as the maximum.
If your car is on wheels that are not the original ones:
- Read your handbook for the axle and sizes it clears. If it clears no chain for your size, the sign still applies to you: where a level accepts tyres instead of chains, only those tyres get you through; where it demands chains, you need wheels the handbook clears for chains, or another car.
- Measure on the wheels actually fitted, with the car on its wheels, engine off and parking brake on; if you need to get under it, only with the car raised and resting on axle stands, never on the jack alone. Width, offset and caliper size change the gaps. Our guides to wheel offset and caliper clearance explain why, and the wheel offset calculator shows how far the inner and outer faces move.
- Try the set at home, on a dry day (our advice), then turn the steering to full lock and look. A chain that touches a strut or a brake hose is a danger, not just a noise; if it has rubbed, have the car checked before you drive on. See wheels or tyres rubbing for where to look.
- Keep under the lowest speed that applies: the device maker's, the car maker's (30 mph for Porsche and Polestar) and the posted one (25 or 30 mph in California).
Frequently asked questions
Do I need chains in California if I have four-wheel drive?
At R-2, no, if all four tyres are snow-tread (M+S) tyres, but you must carry traction devices. At R-3, yes: chains or devices on every vehicle. Caltrans's 2016 sheet asks all vehicles, 4WD included, to carry chains when entering a chain control area.
Are snow socks legal?
In California, if they meet Vehicle Code section 605 (Caltrans lists textile snow chains as an alternative device, which may be restricted locally). In Colorado and Washington, only products on the state's list.
What does Colorado's traction law require in 2025 and 2026?
According to CDOT's November 2025 release: for 4WD and AWD vehicles, tyres with at least 3/16 inch (4.8 mm) of tread marked M+S, all-weather or mountain-snowflake; otherwise chains or a device from CDOT's list on two or more drive tyres. CDOT's traction law page still lets any passenger vehicle use those tyres. It is in force on I-70 between Morrison and Dotsero from 1 September to 31 May, and anywhere CDOT activates it.
What is the fine for ignoring a chain law?
As published on 16 October 2026: Colorado $100 plus $33 on one CDOT page and $50 plus $17 in its November 2025 release; Washington $500; Oregon $800; British Columbia C$121. Caltrans does not publish California's amount.
Are M+S tyres enough?
At the tyre levels: in California with 6/32 inch of tread, in Colorado on a 4WD or AWD with 3/16 inch, in Washington with 4/32 inch. Oregon's traction tyre definition names studs and the mountain/snowflake emblem; M+S appears only in the 4WD exemption.
Which axle do chains go on?
The drive axle: Oregon asks for one tyre on each side of the primary drive axle, and Caltrans's sheet puts them on the front of a front-wheel-drive car. Handbooks can restrict this: Porsche and Polestar allow the rear axle only.
Can I fit chains on 20-inch wheels?
It depends on the car, wheel and tyre. Porsche rules out its own chain set for the Macan (95B) with 20 and 21-inch winter and all-weather wheels; Polestar advises against chains above 20 inches on the Polestar 2. Read the handbook first, then check the gaps against SAE class S.
Wheels from Onyx Forged
Onyx Forged is a French brand of made-to-order forged wheels, designed to JWL/VIA standards. Onyx Forged does not recommend a size or an offset: the room a chain needs is set by your car maker's handbook and the chain maker's fitting list, and customer service sends you, on request, the width, diameter and offset of each wheel so you can check them. See how to customise a set.
Sources
- California: Caltrans, chain controls and Caltrans, chain requirements sheet, revised 10/16, which quote Vehicle Code sections 558 and 605.
- Colorado: CDOT, Traction Law and Chain Law; CDOT, news release of 20 November 2025; Colorado General Assembly, SB25-069.
- Washington: WAC 204-24-040, WAC 204-24-050, RCW 46.37.420, WSDOT, Winter Driving Guide.
- Oregon: TripCheck, Oregon chain law, traction tires and minimum chain requirements; ODOT, Winter Snow Zone.
- British Columbia: enforcement and fines and about winter tires.
- Australia: NSW National Parks, snow driving and snow chains; Transport for NSW, driving in snow; RACQ, getting a grip on snow chains.
- Clearance: Peerless, limited clearance issues (a chain maker's page); Wikipedia, snow chains; Porsche, Macan snow chain instructions, published by NHTSA; Polestar 2 manual, snow chains.
All pages were read on 16 October 2026. Signs override every page above: check the state's road information on the day you travel.
The Onyx Forged design office.