The Maine Department of Transportation is warning motorists who travel Route 1 through Bath to expect months of delays and lane closures as construction begins on a new Bath viaduct.

Workers are completing the demolition of the old viaduct, which carries Route 1 traffic over the city’s historic downtown and onto the Sagadahoc Bridge over the Kennebec River.

Construction of the new viaduct is expected to last through April and the new roadway is scheduled to open by Memorial Day.

Drivers should expect daily lane closures during construction, except for weekday eastbound travel between 3 and 5 p.m. and Saturday westbound traffic between 10 a.m. and 5 p.m., according to the transportation department.

During peak hours, from 3 to 5 p.m., drivers should expect 10- to 15-minute delays, and three- to five-minute delays during off-peak hours.