Tire Chain Laws by State for Trucks: Where You Must Carry and Where You Must Install (2026)

Published September 25, 2026 | TruckerNavi Inc | 14 min read

By the TruckerNavi compliance team, led by Dmitry Borovoy, a New Jersey-licensed insurance producer and author of Safety Manager: From Zero to Expert.

This is a walk-through of published state rules, not legal advice about your particular trip.

The short answer: there is no federal tire chain law. FMCSA does not tell you when to chain up. States write chain rules and states enforce them, and the federal hook is 49 CFR 392.2, which says every commercial motor vehicle must be operated in accordance with the laws, ordinances and regulations of the jurisdiction in which it is being operated. That single sentence is why a Colorado rule binds a New Jersey carrier the moment the tractor crosses into Colorado.

The second thing to get straight before the trip: carrying chains and installing chains are two different obligations with two different triggers. Colorado makes commercial vehicles at 16,001 lbs and above carry chains from September 1 to May 31 on listed corridors no matter how blue the sky is. Washington makes vehicles over 10,000 lbs carry chains on listed routes from November 1 to April 1 regardless of road conditions or advisories, plus two extras. Installing is separate and happens only when a sign says so. Most tickets Russian-speaking owners actually collect out west are for the first one, not the second.

Who writes chain laws, FMCSA or the states?

The states. There is no section of the Federal Motor Carrier Safety Regulations that says a truck must hang chains at a particular elevation, temperature or snow depth. Chain and traction requirements live in state vehicle codes and state administrative rules: Colorado Senate Bill 24-100, Washington RCW 47.36.250 with WAC 204-24-050, the California Vehicle Code, Oregon Administrative Rule Chapter 734 Division 17, Nevada Revised Statutes 484D.520 and 484D.525, Utah Administrative Code R920-6 as UDOT publishes it, and Montana Code Annotated 61-9-406, 61-9-436 and 61-9-520.

Two federal rules still matter on a snowy grade, and neither mentions chains:

• 49 CFR 392.2 imports the state rule. Break the Colorado chain law and you have also failed to operate in accordance with the law of the jurisdiction you are in. The same section adds that where an FMCSA regulation imposes a higher standard of care, the federal rule controls.
• 49 CFR 392.14 catches drivers who chained up and then drove like it was July. It requires extreme caution when snow, ice, sleet, fog, mist, rain, dust or smoke adversely affect visibility or traction, requires speed to be reduced, and requires that operation be discontinued if conditions become sufficiently dangerous. Chains do not repeal that sentence.

Carry versus install: the distinction that produces most tickets

Split every state rule into two questions and the confusion disappears.

1. Must the equipment be in the truck? A seasonal, road-specific equipment duty that does not care about the weather. An officer can open your chain box on a dry September afternoon in the Colorado high country and write you up for what is not in it.
2. Must the equipment be on the tires? A live traffic restriction announced by signs. It cares only about the current condition of the road and can go up and come down within an hour.

Colorado, Washington and Montana all answer question one. California has no answer at all: Caltrans states plainly that the state has no specific dates for carrying chains. But California compensates on question two, where exemptions for heavy trucks are essentially nonexistent. You cannot learn one rule and drive eight states.

Chain laws by state: the working table

Eight states, the ones a westbound load actually crosses. This is not all fifty and it is not meant to be. Verify the live restriction on the state's own travel site before the pass, because the sign, not the table, is the law of that hour.

Why do the weight thresholds keep changing at the state line?

Because each legislature picked its own number and nobody harmonized them. The same tractor is a heavy vehicle in one state and an ordinary one in the next.

Read that column top to bottom on a Los Angeles to Seattle run and you cross 6,500, 10,000 and 12,000 pound thresholds in three states without the truck changing at all.

How does a state actually tell you the requirement is live?

Signs. Always signs. Every state here activates its restriction through posted traffic control devices, backs them with electronic channels, and expects you to obey the sign over anything you heard on the radio.

• Colorado messages requirements through variable message signs, static signs, other official traffic control devices, the CDOT travel website, a telephonic messaging system, email and text. Notifications specify by mile point and by exit number.
• Washington uses one of three statutory sign messages under RCW 47.36.250: traction advisory with oversize prohibited; the same plus vehicles over 10,000 GVW chains required; the same plus all vehicles chains required except all wheel drive.
• Montana uses two formats: signs with flashing beacons reading state law when flashing, chains required for towing units, and signs that flip open.
• Oregon posts snow-zone signs telling you to carry or to use, and layers a conditional road closure on top when that is not enough. On I-5 through the Siskiyou Pass south of Ashland that is a normal winter event, and traction tires stop being sufficient.
• Utah notifies through road signs, message boards, the UDOT traffic app and social media, and warns you may have to comply up to 24 hours before a storm arrives.

Colorado also answers the question everybody asks at the top of the descent: the chain law stays in effect until CDOT says otherwise by sign or notification, or when the centerline or lanes are visible on a descending grade. That is the closest thing to an objective release in any of these codes.

Colorado in detail: the strictest carry rule in the country

Colorado is where an East Coast carrier gets its first surprise, because the state turned a limited I-70 rule into a statewide corridor rule. The CDOT Must Carry program defines a CMV here as a vehicle with a manufacturer's GVWR or GCWR of at least 16,001 pounds used in commerce, or at least 16,001 pounds carrying 16 or more passengers including the driver. RVs at that weight are included, and the expanded law took effect September 1, 2024 under Senate Bill 24-100. The corridors where chains or approved ATDs must be aboard from September 1 through May 31, weather irrelevant: I-70 west of MP 259 (Morrison), CO-9 MP 63 to 97 (Frisco to Fairplay), US 40 west of MP 256 (Empire), US 50 west of MP 225 (Salida), US 160 west of MP 304 (Walsenburg), US 285 west of MP 250 (Morrison), and US 550 from MP 0 to 130.

The scale is not theoretical. In its October 21, 2025 release 1,400 miles, 130 chain stations: Colorado's Must Carry Law, CDOT counts more than 1,300 Must Carry citations written in the 2024-2025 chain season, over 1,400 centerline miles subject to the law, and 130 designated chain stations, of which 22 sit on the I-70 mountain corridor. The station table published on the chain-up tips page is shorter than 130 because it lists the signed stations by roadway, direction and milepost rather than every designated site. Colorado also spells out what others leave vague:

• Trailers do not need chains. Straight answer, stated by CDOT.
• Hazmat placarded vehicles may pass the chain-up signs and install where pavement is snow or ice covered, at a safe location off the traveled portion of the highway.
• Lane discipline while chained. CMVs stay in the right lane unless passing a stalled or slower vehicle would otherwise cost them traction, and return immediately after.
• Cables have conditions. CDOT words it exactly this way for tandem drive axle combinations: if chains are on the 2 outside tires of one drive axle, any tire cable may be used to cover 2 tires on the other drive axle, and AutoSocks may be used to cover those 2 tires instead. AutoSocks and tire cables cannot be used together. On a single drive axle combination no cables are allowed at all.
• Auto transporters get an out. Do not use chains where they put hydraulic lines at risk; use ATDs instead. A unit that cannot chain at all has its travel restricted.

The CDOT Must Carry in-depth fact sheet turns the chain law into a shopping list by configuration. This is the table to hand a driver before the first September dispatch:

One Colorado exposure that has nothing to do with traction and everything to do with the same corridor: from December 1 to March 31 permitted oversize and overweight movement on I-70 between the West Vail exit (173) and Morrison (exit 259) is barred westbound Friday 3 to 8 p.m. and Saturday and Sunday 7 a.m. to noon, and eastbound Saturday and Sunday 3 to 9 p.m. The curfew exemption is narrow: not over 110,000 lbs GVW or any other legal limit, and able to hold 40 mph on the flat, 30 mph on a grade, or the posted minimum if lower.

Washington in detail: carry from November regardless of the sky

Washington's rule for anything over 10,000 pounds is blunt, and it catches owners who read only forecasts. Under WSDOT's chain requirements for vehicles over 10,000 pounds, citing WAC 204-24-050(2)(f):

• From November 1 to April 1 chains must be carried at all times on the listed routes, regardless of conditions or advisories. From April 2 to October 31 only when specifically posted.
• Every vehicle over 10,000 pounds carries at least two extra chains, in case conditions worsen or a chain breaks. The extras are not optional inventory.
• Twelve routes are listed, headed by I-90 between North Bend (MP 32) and Ellensburg (MP 101): I-82 Ellensburg exit 3 to Selah exit 26, SR-97 from MP 145 to the junction, SR-2 Dryden (MP 108) to Index (MP 36), SR-12 Packwood (MP 135) to Naches (MP 187), SR-97 from the SR-14 junction (MP 4) to Toppenish (MP 59), SR-410 Enumclaw to Naches, SR-20 Tonasket (MP 262) to Kettle Falls (MP 342), SR-155 Omak (MP 79) to Nespelem (MP 45), SR-970 MP 0 to 10, SR-14 MP 18 to the US 97 junction (MP 102), and SR-542 Mt Baker Highway MP 22.91 to 57.26.
• Equipment spec: two-sided, not plastic, sufficient hardened metal, at least one cross-chain touching the road at all times. WSP may approve other devices only if equivalent in performance.
• Local delivery relief: no chains needed if you stay outside the chain-required areas and do not cross a mountain pass. Oversize is simply out: permitted movement on mountain passes is prohibited where any of the three signs is displayed, starting with Traction Advisory / Oversized Vehicles Prohibited.

One date wrinkle: WSDOT's driver-facing tires and chains page describes the same duty as November 1 to March 31, while the commercial page states November 1 to April 1. Carry through April 1 and the question never arises.

California in detail: no dates, and almost no exemptions

Caltrans is explicit that California has no dates for carrying chains. What it has is a posting regime with teeth for heavy vehicles:

• When a sign requiring chains is posted, all heavy-duty vehicles over 6,500 pounds gross weight must have chains mounted on the tires to proceed. Exceptions for cars and 4WD with snow tires are posted on the sign itself.
• No exemption for a heavy commercial vehicle with snow tires. Studded tires are not traction devices and may not be used in lieu of chains.
• Chains go on the drive axle. Towing means chains always, and a trailer with brakes needs at least one axle chained.
• Caltrans may run truck screening check points at mountain highway approaches, where every heavy truck stops and shows its chains. Trucks without them are directed back down, with no provision to park at the check point.
• Cables have limits. Usually fine for cars and light trucks, but for big rigs on steep grades they may not be permitted, and whenever chain controls are posted over Donner Pass on I-80 heavy trucks are usually required to have link-type chain on at least the main drive axle.
• The R-1, R-2, R-3 shorthand on the radio is internal Caltrans and CHP language, not posted sign text. R-1 exempts passenger vehicles and light trucks under 6,000 lbs with snow tires on two drive wheels; R-2 exempts 4WD under 6,500 lbs with snow tires on all four; R-3 is chains on everything, and a highway is often closed before R-3 is imposed.

Oregon, Nevada, Utah, Wyoming and Montana: the ones you cross without noticing

Oregon: a statewide rule with conditional closure on top

Oregon applies its chain law to every highway in the state and does the placement math by configuration. A tandem-drive solo commercial vehicle needs chains on two tires on each side of the primary drive axle. A single-drive tractor towing a semi-trailer needs two tires chained on each side of the drive axle plus one on each side of any semi-trailer axle. The weight tiers are light duty at 10,000 lbs GVW or less, medium duty above 10,000 but under 26,001, and commercial at 26,001 and up. The most misread exemption is the four-wheel or all-wheel drive passenger carve-out, and ODOT requires all six of its conditions at once: unloaded weight of 6,500 lbs or less; power delivered to both front and rear wheels; chains carried in the vehicle; mud and snow, all-weather radial, or traction tires on all wheels; not towing another vehicle or a trailer; and not being operated in a manner or under conditions that cause the vehicle to lose traction. Drop any one and the exemption is gone.

Nevada: two conditions and a duty to chain the trailer

Nevada runs only two conditions and says so: it does not use the chains-on-everything level California calls R-3. Under NRS 484D.520, a vehicle or combination at 10,000 lbs gross or combined gross weight or less may satisfy a posted sign with traction devices, tire chains or snow tires, while anything more than 10,000 lbs must be equipped with tire chains. NRS 484D.525 then places them on at least two driving wheels of the motor vehicle and two braking wheels of any trailing vehicle that is equipped or required to be equipped with brakes: a trailer duty Colorado does not impose at all.

A citation detail worth knowing before you argue one. NDOT's own comparison page still cites NAC 484.240, but that regulation was renumbered to NAC 484D.235 and 484D.240 and then repealed outright by LCB File No. R110-23 as duplicative of the statutes. The live authority is NRS 484D.520 and 484D.525. What survives in regulation is construction: NAC 484D.220 defines a tire chain as metal or plastic, two circular loops, one on each side of the tire, connected by not less than nine evenly spaced chains, cables or straps; NAC 484D.225 describes traction devices with traction arms on a central support ring, and lets the DMV Director approve a device that does not match that description. That approval route is how Nevada came to accept alternative devices of durable fabric or plastic wrapping the tread. Nevada snow tires need an M-S sidewall marking and at least 3/16 inch of tread. On SR-431 (Mt. Rose Highway), SR-207 (Kingsbury Grade) and US-50 between Glenbrook and Carson City, anything moving without chains during a restriction must be four-wheel or all-wheel drive with snow tires.

Utah: three classes and a forecast-based trigger

Utah rewrote its rule: the current R920-6 took effect October 23, 2025 and now has three classes of designated traction segment, not two. UDOT names the segments by traffic engineering order and must publish the list with each segment's class on its website and pass it to the Utah Highway Patrol, county offices and local police. Class 1 reaches every vehicle with a GVWR of 12,000 pounds or more: traction devices on all rear drive tires, with only one tire per dual-mounted pair needing one, or AWD/4WD on M+S or 3PMSF tires. Class 2 reaches every vehicle. Class 3 repeats Class 2 and adds a minimum 5/32 inch of remaining tread to the tire-only options, and R920-6-3(3)(b) lets UDOT or police keep a commercial vehicle off a Class 3 segment even when it complies. The department may also run a Class 2 segment as Class 1, or a Class 3 as Class 1 or 2. UDOT identifies the Cottonwood Canyons segments as Class 3 on its own traction page, and states there that a vehicle over 12,000 GVWR meets the requirement with devices on all drive tires, one tire per dual mounting.

What makes Utah different is the clock. The rule defines predicted adverse weather conditions as forecast conditions the department judges likely to exist or begin within a 24 hours window, and traction requirements may be imposed on that forecast alone. Plan a Utah leg on tomorrow's forecast, not today's map. Utah's definition of traction devices is broad: tire chains (metal chains or cables), tire studs, and snow socks, so textile devices count here the way they do not in Washington. Enforcement is a citation for an infraction under Utah Code 41-6a-304 and 41-6a-715.

Wyoming: two levels and the costliest mistake on I-80

Wyoming is the simplest to memorize and the most expensive to misjudge on I-80. Level 1 lets you through on chains, adequate snow tires or all-wheel drive. Level 2 removes the snow-tire option and requires commercial vehicles to have chains on at least two drive wheels at opposite ends of the same drive axle. WYDOT prices it on its own chain law page: $250 for violating the travel restriction, $750 for a violation that results in a highway closure. It also states the obvious in writing: do not stop in the driving lane to install or remove chains.

Montana: year-round, and a duty that reaches tow vehicles

Montana can require chains year-round, because the department may determine at any time that dangerous or unsafe conditions require them in designated areas. When that happens, every vehicle towing a trailer applies chains to the driver wheels of one axle, and MDT states that AutoSocks are an approved alternative. The carry duty is narrower than Colorado's and is young law, added to the code in 2023: under MCA 61-9-436 a motor truck of 26,001 GVW or greater towing a trailer must carry department-approved traction control devices from October 1 through April 30 on a mountain pass or a similar stretch of highway designated as a place where devices are potentially required, and the requirement does not apply to a vehicle with four-wheel drive. Chain-up areas are signed by milepost on named grades including Lookout Pass (I-90 MM 4 to 0 at the Idaho line), Homestake Pass (I-90 MM 228 to 241), Bozeman Hill (I-90 MM 319 to 323), Elk Park Hill (I-15 MM 148 to 143 southbound), MacDonald Pass (US-12 MM 23 to 35), Marias Pass (US-2 MM 192 to 199), Lost Trail Pass (US-93 MM 8 to 0), Lolo Pass, Rogers Pass and Kings Hill. The two fines are separate: $225 for the first failure to carry and $225 to $500 after that, versus $250 for failure to use, rising to $750 when the violation causes an incident that closes all lanes in one or both directions.

What actually counts as a legal traction device?

This is where a carrier buys the wrong equipment once and pays for it every winter. Five families of device, and their legal status is not the same across these eight states.

What happens if you drive past the sign?

Three consequences stack, and only the first is a fine.

1. The citation. Colorado: $100 plus a $32 surcharge for not carrying on the listed corridors, up to $500 plus $78 for noncompliance with winter driving restrictions statewide. Wyoming: $250. Washington: $500 including all statutory assessments under RCW 47.36.250(4). Montana: $225 for a first failure to carry (MCA 61-9-436(2)) and $250 for failure to use (MCA 61-9-520(1)(a)). Oregon: a Class C traffic infraction, escalating to a Class A traffic violation for a commercial driver who fails to carry and use chains and traction tires.
2. The closure charge, which owners underestimate. Colorado sets $1,000 plus a $156 surcharge if you are stuck and blocking any traveled portion of the roadway. Wyoming sets $750 for a violation that results in a highway closure. Montana sets $750 when the violation causes an incident that closes all lanes in one or both directions. Three legislatures wrote three separate numbers for three separate offences, so do not read them as one going rate: read them as the cheapest of the three still costing more than a set of chains.
3. The turnaround. California is explicit that vehicles without chains may not enter chain control areas and must return to a lower elevation, with no provision to park at the check point. Washington may stop chainless vehicles from entering. In appointment terms that is a missed delivery and a driver parked at the bottom of a grade.

Underneath all of it sits 49 CFR 392.14. If the road is bad enough that chains are not making the truck safe, the federal rule says operation shall be discontinued and shall not be resumed until the vehicle can be safely operated. Nobody was ever sued for parking.

Does a chain law violation show up in CSA?

Not by the mechanism most owners assume, and the difference changes what you do after the stop. FMCSA's Safety Measurement System is built from violations recorded on roadside inspection reports. Paying a state citation is not the event that moves a percentile, and neither is a court date. A chain-law citation written on a state form is a state traffic matter and a driver record matter. What can cross into the federal system is a violation written up during an inspection, and the bridge is 49 CFR 392.2, which makes state operating law federally enforceable against a CMV.

So the routine after any western stop stays the same: read the inspection report before you sign it, note whether an inspection was performed at all or you were simply handed a citation, keep the report, and challenge factual errors through DataQs, the only channel that corrects the federal record. The scoring mechanics are in CSA scores explained: BASICs, thresholds and methodology.

One thing worth saying plainly, because vendors blur it: FMCSA does not publish a link between your BASIC percentiles and what an insurer or a broker will do. Treat chain compliance as an operating and liability question first. A truck that slides into a guardrail on Wolf Creek Pass produces a claim file, a preventability question and a driver, all of which cost more than any percentile. How that federal review works is in crash preventability determination.

What belongs in the truck and what belongs in the office?

In the truck, before it leaves the yard in September:

1. A full set for four drive tires, sized to that unit, plus the state extras. Washington wants two spares beyond the working set; Colorado wants four devices on the drive tires for trucks and combinations, two for buses and hot shots, four for duallies pulling trailers.
2. Metal chains at minimum, even if you also carry socks. Socks satisfy Colorado, Montana, Utah and Nevada. Metal satisfies everyone.
3. Bungees, spare cross links, a headlamp, waterproof gloves, a kneeling pad. Chain stations are dark, freezing and slushy, and CDOT says as much in its own driver materials.
4. A pre-trip that opens the chain box. A chain that will not fit or will not close is the same as no chain at a check point, which is exactly what a disciplined daily inspection is for: see the DVIR rules.

Two of these are not winter-specific. A driver who cannot show a device at a check point is the same driver who cannot show a clean pre-trip, and the violations that actually get written on western roadside stops are catalogued in the common DOT violations guide. If the company itself is new and the first winter is also the first season under its own MC number, the paperwork side is in the MC authority activation timeline.

In the office, before the load is dispatched: check the live restriction on the state's own site rather than a third-party map (cotrip.org, WSDOT, roads.dot.ca.gov, TripCheck, UDOT Traffic, WYDOT); know the corridor list by mile point, since Colorado publishes its corridors by mile point and a signed-station table by roadway, direction and milepost, out of 130 designated stations statewide; and write the requirement into the dispatch note, because a driver who learns about the Must Carry season at the Genesee Park chain station is learning it from a trooper. Winter is also not the only exposure on that lane: axle weight on the scales is covered in the bridge formula and axle weights, and the spring inspection blitz in CVSA Roadcheck and Brake Safety Week.

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