Traffic will be completely rerouted by Tuesday evening. There'll be a memorial service of sorts, with a hearse and bagpiper leading attendees.

After more than two years of construction, Hastings is about to trade in its two-lane Mississippi River bridge — an aging and pockmarked powder-blue truss bridge known as "Big Blue" — for a state-of-the-art four-lane bridge that should cut down on congestion and define the city's skyline for a century to come.

In a river town that has always relied on its bridges, and which still mythologizes the old wooden spiral bridge that stood from 1898 to 1951, the switch is a historic moment.

"You know you're coming into Hastings when you come over the hill and see the blue arch," said Norine Bishop, co-owner of Emily's Bakery on Hwy. 61, who said she's crossed the old blue bridge every day. "I will miss the blue arch."

But, Bishop said, she's glad to see the new Hwy. 61 bridge, especially because of the extra lanes. She also likes its clean, modern look.

Construction of the new bridge — it doesn't seem to have a nickname yet — started in 2010 and will be done by the end of 2013. The 1,938-foot, $120 million structure is Minnesota's first free-standing, above-deck arch bridge and constitutes the longest such span in North America, transportation officials said. When it opens to traffic in both directions Tuesday evening, it will be the end of the line for "Big Blue," which will start being dismantled almost immediately.

If the weather cooperates, the memorial service for the old bridge will commence at 6:30 p.m. Tuesday on the north lawn of City Hall, 101 4th St., Hastings. Following a short eulogy from Mayor Paul Hicks, attendees will be allowed to walk on the main span of the old bridge for the last time. Bagpiper Andrew Fox will lead the procession.

About 33,000 vehicles pass over the old bridge each day, making it one of the most-used two-lane spans in the state, said Minnesota Department of Transportation spokeswoman Kirsten Klein. That amount of traffic over the new bridge will put it about in the middle of the pack compared with other four-lane bridges.

Memorial service aside, on Monday afternoon, few people in downtown Hastings were feeling sad about the demise of the old bridge.

It "isn't old enough to be nostalgic," said Tony Berens, owner of a jewelry store started by his grandfather.

Dick Reissner has spent all of his 74 years in Hastings and is the third generation in his family to run Reissner's Meat & Grocery on 2nd Street. He remembers riding his bike across the spiral bridge to a favorite fishing spot where a harbor exists today.

Standing outside the shop Monday afternoon, he and Rick Meyer, 63, said they'd probably go to the memorial service for the old bridge, but Meyer said he's "absolutely" excited about the new bridge.

"This one could go down before the new one gets open," he joked about the old blue bridge. "I've lived in Pittsburgh and New York. When they do this bridge, make sure you have something people want to see on the Mississippi. I think the new bridge is going to work out just fine."

"I think it's going to be a big improvement over what we have," Reissner said. But, he said, "they're going to block off a lot of the side streets. It's going to be hard to get from east to west Hastings. There's going to be some major changes for all us old citizens."

Barb Crist, who has operated Barb's Bridal and Formal Wear since 1998, misses the spiral bridge, despite the fact that she wasn't born yet when it was torn down.

"Our town was founded on the spiral bridge," she said.

The 545-foot arches of the new bridge are designed to withstand crosswinds without the need to connect upper bracing, as is seen on the 360-foot arches in the Cedar Avenue Bridge between Eagan and Bloomington.

The Hastings arch segment was built on five barges in the river in the summer of 2011. The twin-arch span and skeletal steel bridge deck were hoisted onto concrete piers last September. Workers scrambled Monday afternoon to ready two of the bridge's four lanes for traffic.

The state Department of Transportation opened a single southbound lane Monday evening. On Tuesday evening, a single lane will open for northbound traffic.

The bridge's southbound lanes will accommodate all traffic until construction is finished on the northbound approach. The full four lanes will open by late November or early December, a MnDOT spokeswoman said.

Pat Pheifer • 952-746-3284