Helena – Mountain West Holding Company will continue with construction and the placement of the concrete barriers on U.S. Highway 12, between East Helena and Helena, to enhance safety on the elevated roadway, known locally as the viaduct.
Beginning May 15th, Mountain West Holding Company will close the Eastbound and Westbound passing lanes of Highway 12 between Helena and East Helena from reference posts 47 to 49.
The contractor will be working from 7am to 7pm placing concrete barrier rail in the center median. This work should be completed by Friday, May 18th. The passing lanes will be closed 24 hours a day until this work is completed.
Motorists should expect one lane of traffic open in each direction during installation, Zipper merge traffic control, and reduced speeds (35 mph) in the work zone.
Motorists are reminded to watch for work crews, equipment and travel at posted speeds and remember fines are double in work zones. Wide loads are permitted to drive thru the project but still maintain caution. Please watch for workers in the work zone and safe travels.
The East Helena viaduct project was selected based on MDT’s data-driven, strategic approach for the selection and prioritization of safety improvement projects.
“MDT has the proven tools and a rigorous process for reducing serious injury and fatal crashes,” Roy Peterson, MDT’s Traffic and Safety Bureau Chief said. “Going forward we believe these changes will benefit drivers, particularly if the weather is bad or you are unfamiliar with the area.”
What is a zipper merge?
When a lane is closed in a construction zone, a Zipper merge occurs when motorists use both lanes of traffic until reaching the defined merge area, and then alternate in “zipper” fashion into the open lane. The benefits of Zipper merge include more even lane use when approaching a lane reduction. Zipper merging has been found to cut down on traffic wait time, because drivers are able to merge at higher speeds and reduce the length of traffic queues (up to 40%).