Vehicle travel over the Sagamore Bridge will go from two lanes in each direction down to a single 12-foot lane in each direction beginning April 12.

The lane closures are part of repair work to structural steel supports and the bridge lighting system. They'll be in place 24 hours a day until the project is completed, probably before Memorial Day weekend, according to the U.S. Army Corps of Engineers, which owns and operates the bridge.

“The biggest concern we have is that school vacation in Massachusetts also starts the following week," said Cape Cod Chamber of Commerce CEO Wendy Northcross. "All indications are that we have good advance reservations, so people will be traveling here. So, it's incumbent on us now to get the word out that this work will be happening”

Motorists planning to use the Sagamore Bridge should be aware that travel delays are likely to occur during the morning and afternoon peak travel periods each day. All traffic lanes on the Bourne Bridge will remain open while work is occurring on the Sagamore Bridge, but similar repair work is scheduled on that bridge next fall. The aging bridges over the Cape Cod Canal need extensive maintenance work every 2 to 3 years, which Northcross said impacts travel for both residents and visitors.

“This continual maintenance cycle is extremely disruptive, and it just makes the case these bridges are aging and structurally deficient," she said. "We've got a good plan, and the plan needs to happen.”

That plan, approved by the Corps of Engineers, calls for the replacement of both bridges at a cost of $1 billion. Although congressional approval is expected, a spokesman for Rep. William Keating, D-Mass., said that it will be 6 to 7 years before the new bridges are complete.