BANGOR, Maine — If you’re among the 18,000 drivers who use the Union Street bridge in Bangor on a daily basis, you might want to start rethinking your route.

This summer, the Maine Department of Transportation will start the long process of replacing the bridge, which carries four lanes of heavily traveled Union Street over one of the busiest local stretches of Interstate 95.

The two-phase project will cost $8.8 million — 90 percent coming from federal funds and 10 percent from the state — and stretch from this summer into the spring of 2016, according to Maine DOT project manager Steve Bodge. The project went out to bid Wednesday, and a contractor should be selected in the next eight to 10 weeks, he said.

The bridge replacement is among 425 capital projects DOT has scheduled to begin this year with a combined price tag of $455 million. The department released its three-year work plan on Jan. 8, which includes an ambitious list of 1,600 “work items” at a total cost of more than $2 billion. Only projects that begin this year are funded and tied to definite schedules, according to DOT Commissioner David Bernhardt.

The Union Street bridge already gets congested during high-traffic times of day, but in the summer, DOT will shut down the two westbound lanes heading toward the airport. Traffic will still be allowed in both directions over the bridge in the two remaining lanes.

The 54-year-old overpass also has been hit by several oversize loads in the past.

“We know it’s starting to deteriorate,” Bodge said Thursday. Overall, the bridge is in fair to poor condition, he added, but the decking on the bridge is beginning to break up, and the fear is that pieces of concrete might be knocked from the bridge and fall onto the interstate below.

The fact that the overpass stretches over a busy section of I-95 made the project a high priority for DOT, he said. Other bridges in the state are in worse shape, but most of them don’t span over such a busy stretch of road, Bodge said.

Motorists will get plenty of advance notice about detours and traffic changes, according to the city. Signs should be set up in the area well in advance, and the city will put out messages providing the details of detour suggestions once plans are firmly set.

“There are going to be detour routes set up that utilize Hammond and Broadway,” Art Morgan, Bangor’s director of public services, said.

Once the westbound half of the bridge is finished sometime in the spring of 2015, crews will shut down the other half and repeat the process. Eventually the entire bridge will be replaced, according to Bodge. One sidewalk will be kept open on the open side of the bridge throughout the construction process.

Traffic will be a major concern — and headache — throughout the process, city and DOT officials caution. All side streets in the area of the bridge — 15th, 16th and 17th streets, Beecher Park, Eddyway Street, Sunset Avenue and the Bangor Housing Authority driveway — will be closed off from Union Street to prevent vehicles from trying to bypass the bridge by cutting through neighborhoods to get to the parallel Ohio Street.

“We’re trying to eliminate conflicts, eliminate accidents and make this a safer work zone,” Bodge said.

Vehicles will only be able to make right-hand turns when coming onto Union Street from the southbound or northbound lanes of I-95. Motorists will not be allowed to turn left to pass over the bridge because traffic is expected to back up too far in both directions to allow more vehicles in safely. The northbound I-95 on-ramp will remain open, but vehicles heading toward downtown Bangor will not be able to turn left there to enter the interstate.

DOT will build a road to link Sunset Avenue to Texas Avenue to provide a temporary detour for businesses and residents to access that street, which is currently a dead end only accessible via Union Street.

Interstate 95 will be in flux throughout construction, with closures of individual lanes, lane shifts and full closures with detours for about 32 nights during the course of the project, according to Bodge. Those full closures will allow crews to safely remove and replace large sections of beam from the bridge without cars passing underneath.

In October 2013, TRIP, a Washington D.C.-based nonprofit that researches transportation and infrastructure issues, released a 24-page report titled “Maine’s Top 50 Transportation Challenges and Improvements Needed to Address Them.”

The report outlined the pieces of infrastructure across the state that were in the most dire need of attention. The Union Street bridge was listed No. 2 in part because of the amount of traffic it sees on a daily basis and the access it provides to Bangor International Airport and the University of Maine at Augusta’s Bangor campus. Only the $14 million reconstruction of a 4.8-mile section of Route 3 in Bar Harbor was deemed more vital by the organization. That project is scheduled for 2015-16, according to the DOT.

Maine DOT spokesman Ted Talbot said Wednesday that DOT doesn’t keep a numbered list of priority projects, but the importance of the Union Street overpass rebuild is reflected in the fact that it made the state’s work plan.

For a full list of Maine DOT projects scheduled for 2014-16, visit