The Montana Department of Transportation has issued a chains-required restriction for all towing units on US-12 between mile posts 23.0 and 35.0, a stretch of highway that runs through the mountains west of Helena toward Missoula. The restriction was in effect as of October 12 with no specified end date.
US-12 through that corridor climbs through terrain that can deteriorate quickly when winter weather moves in, and towing units — whether pulling trailers, campers, or commercial loads — are especially vulnerable on grades and curves that become treacherous in snow and ice. Drivers who fail to chain up face both safety risks and potential fines.
Residents planning to travel US-12 west of Helena should check MDT's 511 system or the Roads & Travel app before heading out. Conditions in that corridor can change faster than forecasts suggest, and a restriction that's in place at departure may be lifted — or tightened — by the time a driver reaches the affected miles.