A disabled semi-truck was partially blocking the northbound lane of US-12 at approximately milepost 74 on Monday, prompting a traffic advisory for drivers heading westbound on the route, according to Montana Department of Transportation incident reports.
US-12 west of Helena is a primary corridor connecting the capital city to the Avon Valley, Garrison, and points west — a route that sees steady commercial truck traffic alongside passenger vehicles. A partially blocked lane on that stretch, particularly involving a semi, can create significant backup and passing hazards, especially for drivers unfamiliar with the road's shoulder conditions.
Transportation officials advised travelers to use caution and listed the blockage as ongoing with no estimated clearance time in the initial report. Drivers heading out of Helena on US-12 were encouraged to check road conditions before departing.