The Department of Transportation may determine at any time (year-round) that dangerous or unsafe conditions on a highway require tire chains in designated areas where tire chains may be required.
When the Department of Transportation determines tire chains or traction equipment are required, all vehicles towing a trailer (towing units) must apply chains to the driver wheels of one axle. AutoSock's are an approved alternative to tire chains. Designated chain-up and removal area signs are posted in areas where tire chains may be required. Ref: MCA 61-9-406
Studded winter tires are permitted in Montana from October 1 to May 31 of the following year, except that one of those tires may be used for a spare in case of tire failure. School buses equipped with such tires are permitted from August 15 to June 15 of the following year. Ref: MCA 61-9-406
Between October 1 and April 30 of the following year, towing units 26,001 GVW or greater must carry tire chains or an approved traction device when traveling in an area where tire chains may be required. Note: This does not apply to a vehicle with four-wheel drive. Ref: MCA 61-9-436
Current Signs in Use
Signs with flashing beacons affixed
Signs that flip open
Locations Where Tire Chains May Be Required
Tire chains may be required for both directions of travel unless specified in the table below.
| Route | Mile Post | Name | County |
|---|---|---|---|
| I-15 Southbound | 148 - 143 | Elk Park | Jefferson |
| I-15 | 168 - 175 | Boulder Hill | Jefferson |
| I-90 Westbound | 4 - 0 | Lookout Pass | Mineral |
| I-90 | 228 - 241 | Homestake Pass | Silverbow - Jefferson |
| I-90 | 256 - 262 | Cardwell Hill | Jefferson |
| I-90 | 319 - 323 | Bozeman Pass | Gallatin - Park |
| I-90 Eastbound | 548 - 554 | Aberdeen Hill | Big Horn |
| US-2 Westbound | 7 - 4 | Yaak Hill | Lincoln |
| US-2 Eastbound | 179 - 199 | Goatlick Hill and Marias Pass | Flathead - Glacier |
| US-2 Eastbound | 192 - 199 | Marias Pass | Flathead - Glacier |
| US-12 Westbound | 4 - 0 | Lolo Pass | Missoula |
| US-12 | 12 - 30 | Deep Creek Canyon | Broadwater - Meagher |
| US-12 | 23 - 35 | MacDonald Pass | Powell - Lewis and Clark |
| US-20 Westbound | 2 - 0 | Targhee Pass | Gallatin |
| US-87 | 86 - 95 | Lewistown Divide | Fergus |
| US-89 | 25 - 33 | Kings Hill | Meagher - Cascade |
| US-89 Northbound | 71 - 75 | Belt Hill | Cascade |
| US-93 Southbound | 8 - 0 | Lost Trail Pass | Ravalli |
| US-93 Northbound | 4 - 7 | Evaro Hill | Missoula |
| US-191 | 10 - 13 | Fosters Hill | Fergus |
| US-191 Southbound | 14 - 18 | Judith Gap Hill | Wheatland |
| US-191 | 84 - 91 | Missouri Breaks | Fergus - Phillips |
| US-212 | 46 - 54 | Lame Deer Divide | Rosebud |
| US-212 | 80 - 83 | Home Creek Divide | Powder River |
| US-287 | 56 - 64 | Norris Hill | Madison |
| MT-43 Southbound | 4 - 0 | Chief Joseph Pass | Beaverhead - Ravalli |
| MT-200 | 86 - 93 | Rogers Pass | Lewis and Clark |
| MT-287 | 4 - 14 | Virginia City Hill | Madison |
| S-278 | 30 - 35 | Big Hole Pass | Beaverhead |
Montana Codes Annotated
Motor Vehicles
Restrictions As To Tire Equipment
Violation of Tire Chain Or Traction Device Use
Certain Vehicles To Carry Tire Traction Devices During Winter Months