It was the mother of Washington County road projects, lasting three years and transforming a city that had developed a reputation for collisions on cross streets and agonizing waits behind the wheel.

Now the $41 million county mega-project is finished, with new highway overpasses and pedestrian bridges and reconstruction of Forest Lake's once-dangerous Broadway Avenue, the city's main business thoroughfare.

"The downtown area had crumbling infrastructure and massive backups at intersections," said County Engineer Wayne Sandberg, a Forest Lake native.

"If you were a family in a minivan and wanted to go to a restaurant, you had a bigger chance there than anywhere else in Washington County of being T-boned on Broadway."

Traffic in Forest Lake, a city of more than 18,000, had outgrown streets designed years ago when the area's population was far smaller. The city sits at a commuter gateway to St. Paul and Minneapolis and also funnels recreational traffic to nearby lakes.

Broadway Avenue was one of the most notorious stretches of road in Washington County because of its heavy traffic, merging difficulties and high crash rate. The road connects Forest Lake's downtown with Interstate 35 and Columbus in Anoka County.

Improvements along Broadway, also known as County Road 2, are substantial. The street was widened and turn lanes were added, and the county built a "backage" road behind businesses along the north side of Broadway to reduce traffic entering and exiting the busy road.

The Broadway Avenue overpass above I-35 was reconstructed with eight lanes instead of three.

Turn lanes were added as an additional measure to prevent traffic backups.

The work in Forest Lake, which appeared to be one massive project, actually was a series of smaller projects coordinated to follow one after the other, Sandberg said.

"Our goal was to have this look seamless to the public," he said.

Here's what was built in the last three years:

• 2010: County Road 83 overpass over I-35; roundabout at Broadway and Lake Street.

• 2011-2012: Reconstruction of Broadway between 19th Street and Centennial Drive.

• 2011: Reconstruction of the bridge and interchange at Broadway and I-35; extension of 1st Avenue NW. for additional business access; pedestrian bridge spanning Broadway Avenue, creating a safer route for users of the Hardwood Creek Trail.

• 2012: Pedestrian bridge for Hardwood Creek Trail users at County Road 83.

Sandberg said that the combination of projects means that emergency vehicles can cross I-35 quicker, drivers are safer, bottlenecks are eliminated and users of the Hardwood Creek Trail don't have to do battle with Broadway traffic.

Washington County and Forest Lake will celebrate the finished project from 6 to 9 p.m. on Oct. 16 at the American Legion, 355 W. Broadway Av. The public event will include a spaghetti dinner, silent auction and presentation by officials who worked on the project. Money raised at the event will help pay for next year's Forest Lake Independence Day celebration.

In the old days, Sandberg said, Hwy. 61 was the main road through Forest Lake. Now, he said, the city's busiest street -- Broadway Avenue -- will handle traffic 20 years into the future.

The city's older streets and bridges made up "Generation One," he said. "Now we're on Generation Two."

Kevin Giles • 651-925-5037 Twitter: @stribgiles