It’s going to be bad. Very, very bad.

First the Lowry Hill Tunnel, already one of the metro area’s most notorious traffic pinch points, is going to be squeezed even more as motorists in both directions share one side of the tube for three months this spring and summer — and with narrower lanes. Large trucks will be prohibited from using the tunnel and sent on a detour using Crosstown and Hwy. 100, adding more traffic to those already full highways.

And that’s just the start of construction work on Interstate 94 that will have one of the state’s busiest freeways slimmed to two lanes in each direction for 9 miles between Nicollet Avenue in Minneapolis and the Hwy. 252 interchange in Brooklyn Center from April through October.

“There will be [significant] traffic impacts,” said MnDOT project manager Marcell Walker, noting the ripple effect will be felt far beyond the I-94 corridor. “We don’t want to undersell it.”

MnDOT will open bidding Friday for the $57 million pavement rehabilitation and bridge repair project. But with major backups and big delays expected — especially during peak travel periods — the planning began long ago. Transit agencies are drawing up plans to reroute express buses. Ambulance services are studying maps and planning alternate routes. Neighborhoods on both sides of the Mississippi River north of downtown Minneapolis are bracing for an onslaught of traffic as drivers may be tempted to use arterial streets to bypass the work zone.

To get the word out, the agency has sent fliers to thousands of residents in 25 neighborhoods and, in the past week, held the first of more than 40 informal meetings with business leaders and neighborhood groups to explain the breadth and depth of the work. Overwhelmed attendees have reacted with what MnDOT officials are dubbing the “Lowry Look”

“It’s been like, ‘Oh my gosh,’ ” said MnDOT spokesman David Aeikens. “It’s going to be a challenge for folks and it’s going to take longer, there’s no question about that.”

Once a contractor is selected, initial work will begin in late March. Lane closures will begin in April, weather permitting. Over the course of six months, MnDOT will repair more than 50 bridges, rebuild the flyover bridge above Hwy. 252 and repave and rehabilitate the freeway that was originally constructed in the 1980s. Ramps at 49th and Dowling avenues and West Broadway will be closed at times.

“The road is at the end of its life, so we are trying to get 15 more years out of it,” said project engineer Tim Nelson.

The eastbound side of I-94 at the tunnel will be closed first. MnDOT will cut a hole in the medians and switch traffic from one side of the freeway to the other at Hwy. 55 on the west end of downtown and near 3rd Avenue on the east end of downtown.

Compounding matters for the 140,000 drivers that use the freeway each day is that one direction between Hwy. 55 to Shingle Creek Parkway will be closed each weekend during August. The flyover ramp from northbound I-35W to westbound I-94 will be closed while traffic shares the eastbound lanes through the tunnel. When drivers are shifted to the westbound lanes on I-94, the ramp leading to southbound I-35W will be closed and eastbound I-394 drivers won’t have access to eastbound I-94. The entrance from southbound Hwy. 252 to eastbound I-94 will be closed while a new bridge leading from westbound I-94 to westbound I-94/694 in Brooklyn Center is built. The Hennepin and Lyndale exits will remain open.

Lanes in the tunnel will shrink from 12 feet wide to 10 feet, and the speed limit will be reduced to 30 miles per hour.

Nancy Przymus heads the Bottineau Neighborhood Association and is worried her northeast neighborhood may become inundated with cut-through traffic, especially on the third weekend in May when 60,000 come for the Art-A-Whirl festival.

“Our biggest concern is that Hwy. 47 [University Avenue] and East River Parkway and Marshall Street will become a major thoroughfare for people trying to get to work downtown,” she said. “We won’t be able to get in or out of our neighborhood well or safely when this project is up and running. We’ve experienced this before — when 94 gets backed up, northeast neighborhoods get cut off.”

She’s hopeful that Metro Transit might set up temporary park and rides along I-694 to encourage people to take express buses from there.

Metro Transit is not planning for that, but it will reroute 20 express buses over to East River Road to get around potential congestion. Maple Grove Transit’s five express routes will be rerouted to Hwy. 169 and I-394 in an effort to provide the most consistent travel times, spokesmen for the transit agencies said.

Doug Gesme, operations chief for Hennepin Emergency Management Services, said the construction will be inconvenient, but ambulances will use contingency plans. “We will find a way to get to you,” he said.

Steve Cramer, president of the Downtown Council, said real-time communication from MnDOT will be the key for downtown workers.

“It’s not going to be good enough to say there is a big project on I-94 and get ready for it,” he said. “People accessing downtown must be well-informed. They need extensive communication and in real time that says this week here is the impact and two weeks from now, dynamic communication.” To allay fears, he added, “Downtown will continue to function, and you will be able to get in and out of downtown.”

Aeikens said MnDOT plans frequent communication through e-mail, twitter, Facebook and on its project page.

A public open house is scheduled from 4 p.m. to 7 p.m. Feb. 23 at the Minneapolis Park and Recreation Board Building, 2117 West River Road, Minneapolis.

Meanwhile, drivers in the east metro will encounter a second season of lane closures as MnDOT completes a construction project on I-94 between downtown St. Paul and Century Avenue in Maplewood.