Montana Department of Transportation

MDT News

Construction Update On U.S. Highway 12 In East Helena

Helena, Mont. – Mountain West Holding Company will continue
construction and placement of the concrete barriers on U.S. Highway
12 in 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. 

In July, installation of a raised
median at the center of the roadway, new lighting, improved signage
and concrete panel replacement. In addition, the bridge deck of the
viaduct will undergo surface treatment to improve traction and reduce
skidding. Work is scheduled to be completed in November. 

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%).
Learn more @

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.”

Montana’s goal of Vision
Zero is moving the state toward zero deaths and zero injuries on all
Montana roads through education, enforcement, engineering and
emergency medical response. Because one life lost is one too many,
MDT and its partners are united in their mission to save lives on
Montana roads. But they can't do this alone — they need the public’s
help. Commit to Vision Zero, drive safe and make work zone safety a

More information about Montana highway safety programs
can be found at 
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