Road construction is causing lane closures on Interstate 15 between mileposts 217.5 and 221.7, with restrictions in place through 7:00 p.m. Tuesday, September 1, 2026, according to the Montana Department of Transportation. Northbound and southbound single-lane closures are active, with a speed limit reduction to between 45 and 55 mph. A 12-foot width restriction and a 95-foot length restriction are in effect, though the length restriction excludes double and triple combination vehicles. Loads between 95 and 150 feet long or 12 to 18 feet wide must stage in designated wide-load areas and will be marshalled through the construction zone between 4 a.m. and 6 a.m., Monday through Friday. Loads exceeding 18 feet wide or 150 feet long are classified as super loads and must coordinate passage with Mountain West Holding Company by calling 406-490-8390 during business hours, Monday through Friday, 8 a.m. to 5 p.m. Wide-load staging areas are located at reference point 216.0 northbound and reference point 222.5 southbound.