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State Driving Regulations•Winter Safety Reference

Tire Chain Requirements by State

Understanding tire chain requirements by state is essential before driving through winter mountain corridors or declared snow emergency routes. While 31 states permit tire chains whenever snow or ice requires them for safety, 10 Western mountainous states enforce dynamic roadside chain controls, and 8 states enforce declared snow-emergency route restrictions.

Published by TireCalculator.net
Last reviewed: September 2026

State summaries are based on official statutes, administrative rules, and state transportation-agency guidance. Active restrictions can change with road conditions; always check the linked official DOT/511 source before travel.

Calculation MethodologySources & StandardsEditorial PolicyReport a Correction
Direct Answer Summary: 50-State Legal Landscape

How Do Tire Chain Laws Work Across the United States?

Tire-chain rules vary by state across the United States. While 31 states permit tire chains whenever winter weather warrants them for safety, 10 Western mountainous states enforce dynamic roadside chain controls when posted, and 8 states enforce restrictions strictly on declared Snow Emergency Routes. Carrying traction devices inside your vehicle differs legally from actively installing them onto your wheels, and drivers must verify real-time road conditions through official state DOT and 511 systems. State passenger vehicle regulations fall into four distinct statutory categories:

10 States • Required When Posted

CA, CO, ID, MT, NV, NM, OR, UT, WA, WY: Dynamic roadside chain controls activated on mountain passes and steep grades during active winter storms.

8 States • Snow Emergency Routes

MD, MA, MO, NJ, NY, PA, TN, VA: Mandatory chains or snow tires strictly when a formal winter emergency is declared on designated priority clearing arteries.

1 State • Special Restrictions

MI: Chains permitted for safety during snow/ice, but strictly prohibited from damaging bare road surfaces under Michigan Compiled Laws § 257.710.

31 States • Permitted When Needed

Permitted for safety during slippery winter conditions (including Hawaii under HRS § 291-33); no active statewide mandatory pass checkpoints.

Legal Disclaimer & Real-Time Signage Priority

This reference guide synthesizes state statutory codes, administrative regulations, and published DOT winter operational policies for passenger vehicles. Highway departments and law enforcement dynamically establish active chain controls based on real-time pavement conditions, visibility, and incident reports. Roadside illuminated electronic signs, highway advisory radio, and law enforcement instructions supersede general regulatory baselines. Always check current conditions via state 511 traveler information systems before embarking into mountain corridors.

Complete Reference Directory

50-State Traction Law & Chain Requirement Directory

Filter by legal status category or search by state name or postal code. Each entry details passenger requirements, carry mandates, AWD/4WD handling, and official statutory and 511 links.

50-State Tire Chain Laws and Traction Device Requirements for Passenger Vehicles
Alabama(AL)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other slippery conditions.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not differentiate drivetrain requirements.

Alaska(AK)
Permitted When Needed
Passenger Requirement:

Permitted for safety during snow and ice conditions. Must obey posted local or highway travel emergency orders.

Carry Rule: No general passenger carry mandate.
AWD / 4WD & Tires:

State law does not establish a statutory AWD chain exemption.

Arizona(AZ)
Permitted When Needed
Passenger Requirement:

Permitted for safety during ice or snow. ADOT may post emergency chain restrictions on high-elevation routes during severe storms.

Carry Rule: No statutory carry mandate.
AWD / 4WD & Tires:

Follow posted highway emergency signs during high-country winter storms.

Arkansas(AR)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

California(CA)
Required When Posted
Passenger Requirement:

Required when posted under Caltrans and CHP chain controls (R-1, R-2, R-3) on mountain passes. There is no fixed statewide calendar passenger carry law, but vehicles relying on an R-1 or R-2 exception must carry chains.

Carry Rule: Vehicles relying on the applicable R1 or R2 snow-tire/AWD exception must carry chains or traction devices as specified by Caltrans. Other vehicles must install them when the posted control requires it.
AWD / 4WD & Tires:

4WD/AWD vehicles with snow-tread tires (M+S or 3PMSF with min 6/32" tread) on all 4 wheels are exempt from installing chains under R-1 and R-2, but must still carry chains in the vehicle. Under R-3, all vehicles must install chains.

Traction tires: Snow tires must carry M+S, M-S, M/S, or mountain snowflake marking with minimum 6/32" tread depth.

Jump to California Mountain Pass Deep-Dive ↓
Colorado(CO)
Required When Posted
Passenger Requirement:

Required when activated by CDOT under the Passenger Vehicle Traction Law (Code 15) or Passenger Vehicle Chain Law (Code 16). On I-70 between Dotsero and Morrison (MP 133–259), passenger vehicles must continuously meet Traction Law standards from Sept 1 to May 31.

Carry Rule: On I-70 (Dotsero to Morrison, Sept 1–May 31), motorists must have 4WD/AWD with min 3/16" tread, or tires with 3PMSF/M+S with min 3/16" tread, or carry chains/approved ATDs.
AWD / 4WD & Tires:

Under Traction Law (Code 15), 4WD/AWD with min 3/16" tread satisfies requirements without chains. Under Chain Law (Code 16), all passenger vehicles must install chains or approved ATDs regardless of drivetrain.

Traction tires: Requires 3PMSF or M+S designation with minimum 3/16" (4.8 mm) tread depth when Code 15 is active.

Jump to Colorado Mountain Pass Deep-Dive ↓
Connecticut(CT)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions causing slippery highways.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Delaware(DE)
Permitted When Needed
Passenger Requirement:

Permitted for safety during snow and ice. Motorists must observe Governor-declared State of Emergency driving restriction levels during severe blizzards.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not differentiate drivetrain requirements.

Florida(FL)
Permitted When Needed
Passenger Requirement:

Permitted for safety in the rare event of ice or snow as a statutory exception to the metal projection prohibition.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not differentiate drivetrain.

Georgia(GA)
Permitted When Needed
Passenger Requirement:

Permitted for safety during snow and ice. GDOT may declare travel advisories during emergency winter storms in northern mountain corridors.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

Follow emergency roadway restrictions posted on digital message boards.

Hawaii(HI)
Permitted When Needed
Passenger Requirement:

Ordinary detachable tire chains are explicitly permitted by statute on public roads when required for safety.

Carry Rule: No general requirement to carry tire chains on public highways.
Local Note: Under HRS § 291-33, ordinary detachable tire chains are permitted on highways. Access to the Mauna Kea summit access road above Hale Pohaku is subject to specialized local reserve rules.
AWD / 4WD & Tires:

State law does not specify separate highway drivetrain rules.

Idaho(ID)
Required When Posted
Passenger Requirement:

Permitted statewide when required for safety. ITD may post mandatory chain requirements on mountain passes (I-90 Lookout Pass, Fourth of July Pass; US-12 Lolo Pass) during severe winter conditions.

Carry Rule: Passenger requirements depend on active posted restrictions. Check Idaho 511 and roadside electronic signs before travel.
AWD / 4WD & Tires:

4WD/AWD vehicles with adequate traction tires are generally permitted to travel unless signs mandate chains on all vehicles.

Jump to Idaho Mountain Pass Deep-Dive ↓
Illinois(IL)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Indiana(IN)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety during snow, ice, or other slippery road conditions.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Iowa(IA)
Permitted When Needed
Passenger Requirement:

Permitted for safety during snow and ice conditions. Must not damage the highway surface.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not establish a statutory AWD chain exemption.

Kansas(KS)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Kentucky(KY)
Permitted When Needed
Passenger Requirement:

Permitted for safety during winter weather when ice or snow creates hazardous traction.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Louisiana(LA)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety in the event of snow or ice.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not differentiate drivetrain.

Maine(ME)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety during winter driving conditions.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not establish a statutory AWD chain exemption.

Maryland(MD)
Snow Emergency Routes Only
Passenger Requirement:

When an official Snow Emergency is declared on designated Snow Emergency Routes, travel requires tire chains or approved all-season/snow tires on drive wheels.

Carry Rule: No requirement to carry tire chains during normal conditions.
AWD / 4WD & Tires:

Snow tires or all-season radial tires on drive wheels satisfy Maryland Snow Emergency Route requirements.

Jump to Snow Emergency Route Framework ↓
Massachusetts(MA)
Snow Emergency Routes Only
Passenger Requirement:

Permitted for safety during snow and ice. MassDOT and State Police may declare emergency travel restrictions mandating chains or snow equipment during severe blizzards.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

Adhere to declared emergency orders on limited-access highways.

Jump to Snow Emergency Route Framework ↓
Michigan(MI)
Special Restrictions
Passenger Requirement:

Tire chains of reasonable proportions are permitted when required for safety because of snow or ice. However, chains must not directly contact or strike bare highway surfaces causing road damage.

Carry Rule: No requirement to carry tire chains.
Local Note: Under MCL § 257.710, chains are permitted for safety upon snow/ice, but vehicles must not operate on public highways with metal directly striking bare pavement.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Minnesota(MN)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other slippery road conditions.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Mississippi(MS)
Permitted When Needed
Passenger Requirement:

Permitted for safety during snow and ice as a statutory exception to the metal projection rule.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not differentiate drivetrain.

Missouri(MO)
Snow Emergency Routes Only
Passenger Requirement:

Permitted for safety during snow or ice. Required on designated Snow Emergency Routes when an official winter emergency is declared.

Carry Rule: No requirement to carry tire chains during normal travel.
AWD / 4WD & Tires:

Snow tires or all-weather radials on drive wheels generally satisfy declared snow emergency route requirements.

Jump to Snow Emergency Route Framework ↓
Montana(MT)
Required When Posted
Passenger Requirement:

Permitted October 1 through May 31 (or year-round for safety). MDT may post notices requiring passenger chains during severe mountain weather.

Carry Rule: No statutory carry mandate for passenger vehicles.
AWD / 4WD & Tires:

4WD/AWD vehicles with approved winter tires are generally exempt unless signs indicate chains are mandatory on all vehicles.

Jump to Montana Mountain Pass Deep-Dive ↓
Nebraska(NE)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Nevada(NV)
Required When Posted
Passenger Requirement:

Required when posted on dynamic message signs by NDOT/NHP in mountain passes (Tahoe Basin, SR 431 Mt. Rose, US 50 Spooner, SR 207 Kingsbury).

Carry Rule: Strongly advised in mountain zones during winter; required when restrictions are posted.
AWD / 4WD & Tires:

4WD/AWD vehicles equipped with snow-tread tires (M+S or 3PMSF) on all 4 wheels are generally exempt from installing chains under posted controls.

Jump to Nevada Mountain Pass Deep-Dive ↓
New Hampshire(NH)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety during winter weather.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

New Jersey(NJ)
Snow Emergency Routes Only
Passenger Requirement:

Permitted for safety during snow and ice. Required on signed Snow Emergency Routes when an official emergency is declared.

Carry Rule: No requirement to carry tire chains during normal conditions.
AWD / 4WD & Tires:

Snow tires on drive wheels satisfy declared snow emergency route requirements.

Jump to Snow Emergency Route Framework ↓
New Mexico(NM)
Required When Posted
Passenger Requirement:

Permitted statewide for safety. NMDOT may post mandatory chain restrictions on high-elevation passes (e.g., US 64 Palo Flechado Pass) during severe winter storms.

Carry Rule: No statutory carry mandate.
AWD / 4WD & Tires:

4WD/AWD vehicles with adequate traction tires are generally permitted unless signs mandate chains on all vehicles.

New York(NY)
Snow Emergency Routes Only
Passenger Requirement:

Permitted for safety upon snow or ice. Mandatory on designated signed Snow Emergency Routes when an official emergency is declared by the transportation commissioner.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

Snow tires or all-weather tires on drive wheels satisfy declared snow emergency route requirements.

Jump to Snow Emergency Route Framework ↓
North Carolina(NC)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions causing slippery highways.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

North Dakota(ND)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Ohio(OH)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety during snow, ice, or slippery highway conditions.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Oklahoma(OK)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Oregon(OR)
Required When Posted
Passenger Requirement:

Required when posted in designated Snow Zones (e.g., Mt. Hood passes, Santiam Pass, Siskiyou Pass). In Snow Zones, drivers must carry chains or approved traction tires.

Carry Rule: Mandatory to carry chains or qualifying traction tires in posted Snow Zones.
AWD / 4WD & Tires:

Vehicles <= 10,000 lbs not towing may use approved traction tires (3PMSF or M+S with min 4/32" tread) in place of chains when traction tires are permitted by signs. Vehicles towing a trailer are not eligible for the traction-tire exemption and must install chains when posted signs require chains for towing vehicles.

Traction tires: Traction tires with 3PMSF or M+S designation and minimum 4/32" tread qualify for light vehicles not towing in Snow Zones.

Jump to Oregon Mountain Pass Deep-Dive ↓
Pennsylvania(PA)
Snow Emergency Routes Only
Passenger Requirement:

Permitted for safety on snow and ice. Required on signed Snow Emergency Routes when an official emergency declaration is issued by the Governor or PennDOT.

Carry Rule: No requirement to carry tire chains during normal conditions.
AWD / 4WD & Tires:

Snow tires on drive wheels satisfy declared snow emergency route requirements.

Jump to Snow Emergency Route Framework ↓
Rhode Island(RI)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

South Carolina(SC)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety during snow, ice, or slippery road conditions.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not differentiate drivetrain.

South Dakota(SD)
Permitted When Needed
Passenger Requirement:

Permitted for safety during snow and ice. SDDOT and Highway Patrol may post emergency chain restrictions on specific mountain corridors in the Black Hills during major blizzards.

Carry Rule: No statutory carry mandate.
AWD / 4WD & Tires:

Adhere to posted emergency signage in the Black Hills during winter weather.

Tennessee(TN)
Snow Emergency Routes Only
Passenger Requirement:

Permitted for safety. TDOT may enforce emergency chain restrictions on high-elevation passes (e.g., I-40 Monteagle Mountain) during severe winter icing events.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Jump to Snow Emergency Route Framework ↓
Texas(TX)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not differentiate drivetrain.

Utah(UT)
Required When Posted
Passenger Requirement:

Required when posted under UDOT Traction Law. Utah distinguishes Class 2 general highway segments from Class 3 severe mountain corridors (Big Cottonwood SR-190 and Little Cottonwood SR-210), where strict 5/32" tread and equipment standards apply.

Carry Rule: Required on Class 3 canyon routes for vehicles that do not meet qualifying winter tire/drivetrain criteria; required when traction restrictions are activated.
AWD / 4WD & Tires:

On Class 3 canyon segments (Cottonwood Canyons), 4WD/AWD passenger vehicles qualify with M+S or 3PMSF tires having at least 5/32" tread on all 4 wheels. 2WD vehicles must have 3PMSF snow tires with min 5/32" tread on all wheels, or approved traction devices (chains or ATDs) on drive wheels.

Traction tires: Class 3 canyon segments require M+S or 3PMSF rating with minimum 5/32" tread depth for 4WD/AWD qualification, and 3PMSF rating for 2WD passenger vehicles.

Jump to Utah Mountain Pass Deep-Dive ↓
Vermont(VT)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety during winter conditions.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Virginia(VA)
Snow Emergency Routes Only
Passenger Requirement:

Permitted for safety during snow or ice. Required on designated Snow Emergency Routes when an official emergency is declared by the Commonwealth Transportation Board.

Carry Rule: No requirement to carry tire chains during normal conditions.
AWD / 4WD & Tires:

Snow tires or all-weather tires on drive wheels satisfy declared snow emergency route requirements.

Jump to Snow Emergency Route Framework ↓
Washington(WA)
Required When Posted
Passenger Requirement:

Required when posted on mountain pass highways (e.g., I-90 Snoqualmie Pass, US 2 Stevens Pass, US 97 Blewett Pass, US 12 White Pass) under WSDOT traction advisories.

Carry Rule: Strongly advised for passenger vehicles traveling mountain passes in winter; required when signs post chain requirements.
AWD / 4WD & Tires:

When "Chains Required Except AWD" is posted, 4WD/AWD vehicles equipped with approved traction tires on all 4 wheels are exempt from installing chains. When "Chains Required on All Vehicles" is posted, all vehicles (including 4WD/AWD) must install chains.

Traction tires: Traction tires with M+S or 3PMSF and minimum 4/32" tread satisfy "Traction Tires Required" advisories for passenger vehicles.

Jump to Washington Mountain Pass Deep-Dive ↓
West Virginia(WV)
Permitted When Needed
Passenger Requirement:

Permitted when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Wisconsin(WI)
Permitted When Needed
Passenger Requirement:

Tire chains of reasonable proportions may be used on any vehicle when required for safety because of snow, ice, or other slippery conditions.

Carry Rule: No requirement to carry tire chains.
AWD / 4WD & Tires:

State law does not specify separate AWD rules.

Wyoming(WY)
Required When Posted
Passenger Requirement:

Required when posted on dynamic signs by WYDOT under Level 1 (Hazardous) or Level 2 (Extremely Hazardous) chain law restrictions.

Carry Rule: Advised in mountain corridors; required when traveling routes under active restrictions.
AWD / 4WD & Tires:

Under Level 1, vehicles may travel with chains, adequate snow tires (min 4/32" tread), or AWD/4WD. Under Level 2, travel is restricted to vehicles with tire chains on drive wheels OR all-wheel-drive/4WD equipped with M+S or all-weather tires.

Traction tires: Snow tires must carry M+S or all-weather rating with minimum 4/32" tread depth.

Jump to Wyoming Mountain Pass Deep-Dive ↓
Figure 1: Traveler Verification Process

How to Check Tire Chain Requirements Before Travel

Verification Workflow
HOW TO CHECK TIRE CHAIN REQUIREMENTS BEFORE TRAVELStep-by-step traveler verification process for winter road and pass conditions1. IDENTIFY STATE & ROUTECorridor Context• Western mountain pass corridor• Priority snow emergency route• Interstate vs secondary highwayState rules govern per route segment2. CHECK OFFICIAL DOT / 511Official Traveler Info• State 511 traveler maps and apps• Highway electronic message signs• Highway advisory radio (HAR)Live conditions dictate active requirements3. READ ACTIVE RESTRICTIONSPosted Control Tiers• Traction advisory / caution• Conditional restriction (R-1/R-2, Code 15)• Mandatory restriction (R-3, Code 16)Confirm if carry or mount is ordered4. CHECK VEHICLE SPECSVehicle Parameters• Drivetrain: FWD, RWD, AWD, or 4WD• GVWR class (under vs over 10,000 lbs)• Towing status (towing often requires chains)Drivetrain alone never guarantees exemption5. VERIFY TIRES & DEVICESEquipment Verification• Tire markings: 3PMSF vs M+S vs summer• Tread depth: meets state minimums• Traction device fitment and classWorn tires invalidate traction tire pathways6. CARRY OR INSTALLExecution Action• CARRY: Stowed accessible in vehicle• INSTALL: Mounted on specified wheels• Use designated chain-up pullouts safelyFollow equipment-specific speed restrictionsVerification Process Notice: State-Specific Statutes & Real-Time DOT Controls GovernThis workflow outlines traveler verification steps. Active highway restrictions are established dynamically by state DOTs and law enforcement,not by a single universal legal decision algorithm.
Figure 1: Recommended 6-step process for checking tire chain requirements before travel. Current restrictions are established dynamically by official state DOT and 511 traveler information systems. State-specific statutes and active road-control levels govern equipment requirements.
Figure 2: Operational Comparison

Carrying Traction Devices vs. Installing Traction Devices

Compliance Comparison
CARRYING TRACTION DEVICES VS. INSTALLING TRACTION DEVICESUnderstanding the operational and legal distinction between carry requirements and mounting ordersCARRYMeaning: Stored In The VehicleTraction devices are stored securely and accessibly in thevehicle when an applicable carry requirement applies.Operational Key Points:• Kept readily accessible in cargo area or trunk• Pre-verified for exact tire size and wheel clearance• Enforced during active controls in designated mountain corridorsCarry rules do not automatically mean installation will occurINSTALLMeaning: Mounted On The WheelsTraction devices are fitted to the tires/axles required bythe active road-control rule, vehicle manual, and device specs.Operational Key Points:• Mounted and tensioned before passing active checkpoints• Installed on drive wheels according to vehicle manual• Obey device speed limits (typically 25–30 mph maximum)Must be removed when driving on clear bare pavementExact requirements depend on the state, route, vehicle, and active road-control level.Never assume a universal drivetrain exemption or that one tire specification satisfies all jurisdictions.
Figure 2: Distinction between carrying traction devices inside the vehicle and physically installing them on designated wheels. Exact requirements depend on the state, route, vehicle, and active road-control level.
Regional Corridor Analysis

Western Mountain Pass Chain Controls: State-by-State Deep Dive

In Western mountainous states, chain laws are not theoretical—they are dynamically enforced via roadside checkpoints, illuminated signs, and variable control levels. Here is how active chain controls function in the 9 primary Western pass states.

California (CA)

Caltrans Chain Control Levels (R-1, R-2, R-3)

California Vehicle Code §§ 27459, 27460 & Caltrans Chain Controls

Active Control Levels & Drivetrain Rules:

Requirement 1 (R-1)

Requirement: Chains are required on all vehicles except passenger vehicles and light-duty trucks under 6,000 lbs gross weight equipped with snow-tread tires (M+S or 3PMSF with min 6/32" tread) on at least two drive wheels. Vehicles towing trailers must install chains on drive wheels.

AWD/4WD Rule: Both 4WD/AWD and 2WD passenger vehicles under 6,000 lbs qualify for the installation exemption under R-1 if equipped with qualifying snow tires on drive wheels, but chains must still be carried inside the vehicle.

Requirement 2 (R-2)

Requirement: Chains required on all vehicles except 4WD/AWD passenger vehicles with snow-tread tires on all four drive wheels.

AWD/4WD Rule: 4WD/AWD exempt from mounting chains ONLY if snow-tread tires are fitted on all 4 wheels AND tire chains are carried inside the vehicle.

Requirement 3 (R-3)

Requirement: Chains required on ALL vehicles without exception, including 4WD/AWD.

AWD/4WD Rule: No exceptions. Caltrans typically closes highway corridors (e.g. I-80 Donner Summit, US-50 Echo Summit) before invoking R-3 for general traffic.

Passenger Carry Rule:

Vehicles relying on the applicable R1 or R2 snow-tire/AWD exception must carry chains or traction devices as specified by Caltrans. Other vehicles must install them when the posted control requires it.

Key Practical Takeaway:

California maintains no fixed statewide seasonal passenger carry calendar. However, when traveling through active R-1 or R-2 zones, vehicles relying on a snow-tire or 4WD/AWD installation exception must carry chains in the vehicle.

Colorado (CO)

CDOT Passenger Traction Law (Code 15) vs Chain Law (Code 16)

Colorado Revised Statutes § 42-4-106 & CDOT Winter Driving Regulations

Active Control Levels & Drivetrain Rules:

Passenger Traction Law (Code 15)

Requirement: All passenger vehicles must have: (1) 4WD or AWD with at least 3/16" (approx 6/32") tire tread depth, OR (2) 2WD vehicle with winter tires (mountain snowflake or M+S) with at least 3/16" tread, OR (3) any vehicle equipped with tire chains or approved alternative traction devices (ATDs).

AWD/4WD Rule: AWD/4WD qualifies with minimum 3/16" tread depth without installing chains.

Passenger Chain Law (Code 16)

Requirement: Every passenger vehicle must have tire chains or approved alternative traction devices (such as AutoSock) installed on two or more drive tires.

AWD/4WD Rule: No AWD/4WD exemption. When Code 16 is posted and active on highway corridors (such as I-70 between Dotsero and Morrison), all passenger vehicles must install chains or approved ATDs.

Passenger Carry Rule:

Passenger vehicles are not subject to a statewide carry calendar, but must be equipped with chains or approved ATDs if they cannot meet Code 15 tire/tread standards, or to prepare for active Code 16 chain controls.

Key Practical Takeaway:

The commercial carry mandate (Sept 1–May 31 on I-70 between MP 133 and 259) applies strictly to commercial vehicles 16,001+ lbs GVWR. Passenger cars follow Code 15 and 16.

Oregon (OR)

ODOT Conditional Chain Law & Traction Tire Exceptions

Oregon Administrative Rules (OAR) Chapter 734, Division 17

Active Control Levels & Drivetrain Rules:

Snow Zones / Chains Required

Requirement: Active when signs indicate "Chains Required" or "Traction Tires Required". Vehicles with a gross vehicle weight rating (GVWR) of 10,000 lbs or less not towing a trailer may use traction tires instead of chains.

AWD/4WD Rule: 4WD/AWD vehicles 10,000 lbs or less not towing may substitute traction tires (3PMSF rated or studded tires in season) when chains are required for standard vehicles.

Towing Vehicles Under Active Chain Restrictions

Requirement: When roadside signs post a chain requirement, vehicles towing a trailer must install chains on drive wheels and at least one axle of the trailer; towing vehicles are not eligible to substitute traction tires for chains.

AWD/4WD Rule: No traction-tire substitution for towing vehicles when chains are posted. 4WD/AWD does not exempt a towing vehicle from chain requirements.

Passenger Carry Rule:

Drivers entering posted snow zones must carry chains or qualifying traction tires as required by conditions and signage.

Key Practical Takeaway:

In Oregon snow zones, towing vehicles cannot substitute traction tires for chains when chains are posted, and must install chains when required by signage.

Washington (WA)

WSDOT Mountain Pass Chain Requirements & WSP Approved Devices

RCW 47.36.250 & Washington Administrative Code (WAC) 204-24

Active Control Levels & Drivetrain Rules:

Traction Tires Required

Requirement: Passenger vehicles under 10,000 lbs must have approved traction tires (3PMSF, M+S, or studded). Oversize loads and vehicles over 10,000 lbs must install chains.

AWD/4WD Rule: AWD/4WD vehicles exempt from chains if equipped with approved traction tires on all wheels.

Tire Chains Required

Requirement: All vehicles must install chains on drive tires, except 4WD/AWD vehicles under 10,000 lbs that are equipped with traction tires on all four wheels.

AWD/4WD Rule: AWD/4WD vehicles with traction tires are exempt from installing chains, but WA law explicitly mandates that AWD/4WD vehicles MUST CARRY chains in the vehicle.

Chains Required on All Vehicles

Requirement: Extreme storm condition. ALL vehicles including 4WD/AWD must physically install tire chains.

AWD/4WD Rule: No exemptions. When WSDOT posts "Chains Required on All", all vehicles must chain up before passing checkpoint.

Passenger Carry Rule:

Under WAC 204-24-050, 4WD/AWD passenger vehicles are required to carry chains or approved alternative traction devices inside the vehicle when chain requirements are posted on mountain passes.

Key Practical Takeaway:

Commercial vehicles over 10,000 lbs GVW have a mandatory pass carry calendar (Nov 1–Apr 1), while passenger vehicles must carry chains when pass conditions require them.

Wyoming (WY)

WYDOT Level 1 vs Level 2 Road Restrictions

Wyoming Statutes § 31-5-956 & WYDOT Winter Operating Procedures

Active Control Levels & Drivetrain Rules:

Level 1 Restriction

Requirement: Travel restricted to vehicles equipped with tire chains, or adequate snow tires (M+S or 3PMSF with minimum 4/32" tread), or all-wheel drive.

AWD/4WD Rule: AWD/4WD passenger vehicles qualify under Level 1 with adequate tread depth.

Level 2 Restriction

Requirement: Commercial vehicles must install chains. Passenger vehicles must have chains, approved traction devices, or all-wheel drive with adequate snow tires.

AWD/4WD Rule: AWD/4WD vehicles retain an installation exemption under Level 2 provided they are equipped with qualifying snow tires meeting minimum 4/32" tread depth.

Passenger Carry Rule:

Chains required when conditions dictate and signs are illuminated on mountain corridors (e.g. Teton Pass WY-22, South Pass WY-28).

Key Practical Takeaway:

Wyoming maintains a clear pathway for AWD/4WD vehicles with adequate snow tires under Level 2, but drivers must monitor WYDOT message boards for emergency closures.

Nevada (NV)

NDOT Sierra Mountain Corridor Controls (Tahoe & SR 431)

Nevada Revised Statutes (NRS) 484D.515 & NDOT Chain Controls

Active Control Levels & Drivetrain Rules:

Chains or Snow Tires Required

Requirement: Vehicles must have snow tires (M+S or 3PMSF) on drive wheels, or tire chains installed.

AWD/4WD Rule: AWD/4WD permitted with all-season or winter tires in good condition.

Chains Mandatory (Except 4WD/AWD with Snow Tires)

Requirement: All vehicles must install chains, with an exemption for 4WD/AWD vehicles having snow tires on all four wheels.

AWD/4WD Rule: 4WD/AWD exempt from installation if snow tires are on all drive wheels and chains are carried in vehicle for emergency deployment.

Passenger Carry Rule:

Under NRS 484D.515, vehicles entering posted chain-control zones must be equipped with chains or qualifying snow tires as specified by posted signage.

Key Practical Takeaway:

Nevada aligns closely with Caltrans standards across the Lake Tahoe basin and Sierra passes.

Utah (UT)

UDOT Traction Law & Cottonwood Canyon Class 3 Requirements

Utah Code § 41-6a-1636 & Utah Admin. Code R920-6 (UDOT)

Active Control Levels & Drivetrain Rules:

Class 2 Traction Segments (General Highway Passes)

Requirement: Applies to general state highway segments when adverse weather traction restrictions are posted. Vehicles must be equipped with approved traction tires or traction devices (chains or approved alternative traction devices) on drive wheels.

AWD/4WD Rule: 4WD/AWD passenger vehicles qualify with adequate winter or all-season traction tires.

Class 3 Traction Segments (Cottonwood Canyons SR-190 & SR-210)

Requirement: Activated dynamically by UDOT during severe winter weather or before impending storms (typically within the Nov 1 – May 1 winter season). All vehicles must meet strict Class 3 criteria: (1) 4WD/AWD with M+S or 3PMSF tires having at least 5/32" tread on all 4 wheels, OR (2) 2WD vehicles with 3PMSF-rated snow tires on all 4 wheels with at least 5/32" tread, OR (3) approved traction devices (chains or alternative devices) on drive wheels.

AWD/4WD Rule: 4WD/AWD vehicles qualify without installing chains ONLY when equipped with M+S or 3PMSF tires with at least 5/32" tread depth on all four driven wheels.

Passenger Carry Rule:

On Class 3 canyon routes, passenger vehicles that do not meet qualifying winter tire/drivetrain criteria must carry chains or approved alternative traction devices when restrictions are active.

Key Practical Takeaway:

UDOT activates Class 3 Traction Law dynamically based on weather and pavement conditions (and may activate requirements in advance of an impending storm); travelers must verify status via electronic signs, flashing beacons, or the UDOT Traffic app.

Montana (MT)

MDT Mountain Pass Advisory & Restriction Framework

Montana Code Annotated (MCA) § 61-9-406 & MDT Travel Guidance

Active Control Levels & Drivetrain Rules:

Posted Mountain Pass Restrictions

Requirement: Triggered when MDT determines severe conditions exist on designated mountain passes. Signs specify whether chains are required for all vehicles or heavy commercial vehicles.

AWD/4WD Rule: Passenger vehicles are governed by posted signs; 4WD/AWD vehicles with adequate traction tires satisfy moderate advisories unless signs mandate chains on all vehicles.

Passenger Carry Rule:

Passenger requirements depend on the posted restriction. Check MDT 511 and roadside signs before entering mountain passes.

Key Practical Takeaway:

Montana pass signage can escalate rapidly; watch roadside electronic signs and MDT 511 travel maps.

Idaho (ID)

ITD Mountain Pass Chain Requirements

Idaho Administrative Code IDAPA 39.03.01 & Idaho Code § 49-948

Active Control Levels & Drivetrain Rules:

Pass Restrictions (Lookout Pass & Lolo Pass)

Requirement: Active when posted on electronic message signs. Heavy commercial vehicles must chain up; passenger vehicles must have chains or adequate snow tires.

AWD/4WD Rule: AWD/4WD vehicles with adequate winter tires are permitted during passenger advisories.

Passenger Carry Rule:

Passenger requirements depend on active posted restrictions. Check Idaho 511 and roadside electronic signs before travel.

Key Practical Takeaway:

Under Idaho Code § 49-948 and ITD policies, drivers must obey illuminated electronic signs posting chain or traction requirements on mountain pass routes such as I-90 Lookout Pass.

Eastern & Midwestern Framework

Snow Emergency Route Laws: How They Differ from Western Mountain Controls

Eight states—primarily in the Mid-Atlantic, Northeast, and Midwest—do not have regular mountain pass chain checkpoints. Instead, their traction mandates operate exclusively under a Snow Emergency Route framework.

Western Mountain Pass Control Framework

Dynamic, Condition-Triggered En-Route Controls

Western mountain states use different posted traction-control systems. Carry, installation, AWD/4WD, tire, and device requirements vary by state and control level.

  • •Activated dynamically based on live mountain pass weather and pavement conditions.
  • •Communicated via roadside electronic message signs, highway advisory radio, and state 511 systems.
  • •Specific carry mandates and drivetrain exemptions vary by state; see state-specific sections below.
Eastern Snow Emergency Route Framework

Event-Driven Priority Arterial Restrictions

Requirements vary by jurisdiction and declared emergency. Some states permit qualifying snow or traction tires instead of chains on designated routes; check the state-specific rule and current emergency order.

  • •Triggered only when a formal municipal, DOT, or gubernatorial weather emergency is declared.
  • •Applies strictly to designated emergency priority clearing routes rather than entire state highway networks.
  • •Permissible equipment (chains or snow tires) depends on the governing statutory definition and declaration terms.
Maryland (MD)Md. Code Transp. § 22-405.2

When a snow emergency is declared by the Maryland State Police, travel on designated State Snow Emergency Routes is restricted to vehicles equipped with tire chains or snow tires.

Massachusetts (MA)720 CMR 9.03 & MassDOT Regs

MassDOT and municipal authorities declare emergency snow restrictions during severe blizzards. Vehicles traveling on posted emergency arteries must have adequate traction equipment or winter tires.

Missouri (MO)Mo. Rev. Stat. § 304.240

Designated emergency snow routes require tire chains or qualifying winter tires during declared emergencies on priority state highways.

New Jersey (NJ)N.J.A.C. 16:30-3.6 & Title 39:3-73

During declared emergencies on posted New Jersey snow emergency routes, driving without tire chains or snow tires on drive wheels is prohibited when roads are snow-covered.

New York (NY)N.Y. VTL § 375(35-a)

During a declared snow emergency, vehicles operating on designated Snow Emergency Routes must be equipped with tire chains or snow tires on drive wheels.

Pennsylvania (PA)75 Pa.C.S. § 4525

When an official highway snow emergency is declared, vehicles operated on designated emergency routes must be equipped with tire chains or qualifying all-season/snow tires.

Tennessee (TN)Tenn. Code Ann. § 55-9-106

Tire chains or traction equipment are permitted when weather conditions warrant, with travel restricted during declared emergency operations to vehicles equipped with chains or traction tires.

Virginia (VA)Va. Code Ann. § 46.2-1044

Operating a motor vehicle on highways designated as snow emergency routes during declared emergencies requires vehicles to be equipped with tire chains or snow tires on drive wheels.

Commercial Fleet & Heavy Truck Boundary Callout

This guide covers tire chain and traction device regulations strictly for passenger cars, light trucks, crossovers, and passenger vans (typically vehicles under 10,000 lbs GVWR). Commercial vehicle rules may impose different weight thresholds, chain counts, axle-placement requirements, and seasonal carry mandates.

Mandatory Carry Calendars

Commercial vehicles face statutory carry windows regardless of current weather (such as designated pass corridors in Colorado or Washington).

Specific Axle Configurations

Truck laws dictate exact chain placement across drive tandems, single axles, and trailer drag axles.

Dedicated Commercial Divisions

Commercial motor carriers operate under specialized state transportation divisions and carrier safety standards that do not apply to personal passenger vehicles.

Commercial drivers and fleet operators should consult official state DOT commercial-vehicle guidance (and our dedicated commercial chain-law guide when published) for specific multi-axle placement charts and carrier requirements.

Interactive Fitment Tool

Find Matching Tire Chains for Your Exact Tire Size

Launch Chain Calculator

If your state or route requires chains, use our Tire Chain Size Calculator to match your tire size to verified manufacturer-listed traction-device part numbers, with Class S and clearance information where published.

Direct Tire Size LookupSAE Class S GuidancePeer Cross-Reference Table
Common Questions & Practical Answers

Frequently Asked Questions About State Tire Chain Laws

Methodology & Regulatory Provenance

Authoritative Primary Sources & Legislative References

State summaries are based on the cited statutes, administrative rules, and official transportation-agency guidance. Where road conditions or control levels change dynamically, the linked official DOT/511 source should be treated as the current operational reference. Key primary statutory references include:

CaliforniaCal. Veh. Code §§ 27459, 27460 & Caltrans Chain Control Guidance
ColoradoColo. Rev. Stat. § 42-4-106 & CDOT Winter Rules
OregonOr. Admin. R. 734-017 & ODOT Snow Zones
WashingtonWash. Rev. Code § 47.36.250 & WAC 204-24
WyomingWyo. Stat. § 31-5-956 & WYDOT Operating Policy
UtahUtah Code § 41-6a-1636 & Utah Admin. Code R920-6
Related resources:Tire Chain Size Calculator•Winter Tires vs All-Season Tires•How to Read Tire Size•Sources & Standards