Montana Tire Chain Laws

How Montana handles chains

$250 is the fine for skipping chains when MDT posts the order, and $750 if you close all lanes (MCA 61-9-520). From October 1 to April 30, towing units at 26,001 pounds and up must carry chains (MCA 61-9-406). When the signs and flashing beacons go up on passes like Lookout on I-90, US-2 Marias, US-12, US-93, and I-15, chain the driver wheels of one axle. AutoSock is an approved alternative. Four-wheel drive is exempt. Check MDT 511.

When, where, and what counts

• When required: October 1 to April 30, towing units 26,001 pounds GVW and up must carry chains or an approved traction device. Chains actually go on only when MDT posts the requirement at a designated pass, shown by signs and flashing beacons.
• Where: Designated passes and corridors including Lookout Pass on I-90, I-15, US-93, US-12, and US-2 over Marias Pass, among roughly two dozen posted locations across the state.
• Applies to: Vehicles towing a trailer (towing units) rated 26,001 pounds GVW and up. Four-wheel-drive vehicles are exempt.
• Chains vs traction devices: When MDT posts the order, a vehicle towing a trailer chains the driver wheels of one axle. AutoSock is an approved alternative to tire chains. Four-wheel-drive vehicles are exempt from the carry and chain requirement. Snow tires alone do not satisfy a posted chain requirement.
• Check the live order: MDT 511 (roadreport.mdt.mt.gov or dial 511) for the active chain order; flashing beacons and signs at designated passes show when chains are required.
• Fine: $250 for the violation, and $750 when the violation causes the closure of all lanes in one or both directions of a highway (MCA 61-9-520).

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