BATH — With the old viaduct completely demolished and construction of a replacement in progress, the Maine Department of Transportation issued a traffic advisory last week explaining the impact on traffic over the coming months.

Motorists can expect lane closures each day through April, except for eastbound travel from 3-5 p.m. Monday through Friday, and westbound on Saturday from 10 a.m.-3 p.m., according to DOT.

Delays at off-peak times could run three to five minutes, and 10-15 minutes during the 3-5 p.m. peak.

“Southbound U.S. Route 1 travelers should please use both lanes when crossing the Sagadahoc Bridge from Woolwich to Bath, and execute alternate merging at the end of the bridge,” Glenn Philbrook, DOT project resident manager said in the advisory, noting that using both lanes to queue before merging helps keep traffic flowing efficiently.

All downtown businesses will remain accessible during the project.

Information on the project can be found online at maine.gov/mdot/projects/bathviaduct.

The bridge-like viaduct, which carried U.S. Route 1 traffic over the heart of Bath, closed Oct. 11 for a seven-month reconstruction project. Until Memorial Day, motorists are being diverted to “frontage roads,” including Leeman Highway and Commercial Street.

The total project cost is $15.1 million, including $1.9 million for preliminary engineering, $12.7 million for construction and $500,000 for construction engineering, according to DOT Project Manager Joel Kittredge. Federal and state funds are going into the project.

The original viaduct, built in 1958, had a superstructure that reached the end of its useful life and needed more comprehensive work, Kittredge said in a 2014 interview.

Although most of the structure’s piers – which supported the load – at first were expected to remain in place and be rehabilitated or repaired, further analysis of construction, engineering and economics led to a decision to replace all of them.

The reconstructed viaduct will have a life of more than 80 years, according to DOT.

Alex Lear can be reached at 781-3661 ext. 113 or alear@theforecaster.net. Follow him on Twitter: @learics.

In the next several months as Bath’s viaduct is reconstructed, southbound U.S. Route 1 travelers should use both lanes when they cross the Sagadahoc Bridge from Woolwich to Bath, and then plan to alternately merge at the end of the bridge.