It's not often that commuters cheer about a road construction project that will add chaos to their drives, but one that started Monday in Plymouth is getting applause.

For more than a decade, city leaders and citizens have wanted a third general-purpose lane on both directions of Interstate 494 between Hwy. 55 and the Fish Lake interchange, where I-694, I-94 and I-494 come together.

After lots of political wrangling and efforts to secure funding, the Minnesota Department of Transportation got to work Monday on the $68 million job.

Orange signs went up last week warning commuters about construction that will bring lane closures and delays for the next three years. When finished, the extra lane is expected to ease congestion for the 95,000 vehicles that use the segment each day. That number is expected to grow to 133,000 by 2030.

"This is an opportunity to relieve congestion, improve public safety, decrease commute times and allow Plymouth businesses to better serve their customers," said the city's mayor, Kelli Slavik. "I expect that there will be frustration over the next three years as construction progresses, but the end result will be a benefit to not just Plymouth residents, but all drivers that have had to deal with the congestion of three lanes compressing down to two as they drive through Plymouth."

The first order of business is to remove guardrails and put up concrete barriers at the Schmidt Lake Road, County Road 47 and the Canadian Pacific Railroad bridges. They will be the first of the 11 bridges to be replaced or widened between now and 2016.

Motorists can expect night and weekend road closures at times through November, but no full closures are planned.

MnDOT expanded I-494 through Bloomington, Eden Prairie and Minnetonka over the past decade, but funding ran short and priorities changed when it came time to build a third lane in Plymouth. That left the 6-mile segment from Hwy. 55 to the Fish Lake interchange as the only portion of I-494 without three lanes in each directions.

With funding unavailable, MnDOT floated the idea of adding a dynamic shoulder lane, an extra-wide shoulder that would be opened to traffic during peak periods and in emergency situations only.

Slavik said the city kept pushing for the extra lane.

Earlier this year, MnDOT said it had found the money to pay for the long-desired project. MnDOT identified $50 million in savings from other construction projects and allocated some of that money for the third lanes on I-494.

Tim Harlow • 612-673-7768

Twitter: @stribdrive