METHUEN — Construction is expected to begin this fall on the long-awaited overhaul of the Interstate 93 rotary, but motorists could see early indicators of the project — barrels and jersey barriers — popping up by summertime.
"We're at a point where we're approaching 100 percent design," said Dennis DiZoglio, executive director of the Merrimack Valley Planning Commission. "I think they might see some activity in the middle of next year."
The state and federal government are spending $60 million to replace the traffic-riddled rotary at the confluence of I-93 and routes 110 and 113 with a "partial cloverleaf-type" interchange, along with a number of new traffic signals and access ramps.
The project is expected to take 3 to 3 1/2 years to build and is being designed to reduce traffic congestion and improve safety at what is now considered one of the region's most dangerous intersections.
The state is expected to put the project out to bid in late spring and construction is slated to begin this fall, according to Massachusetts Department of Transportation Spokeswoman Sara Lavoie.
"MassDOT is pleased to be advancing this project into construction this year," wrote Lavoie in an emailed statement. "Coordination and involvement with various stakeholders has been positive and we look forward to the safety improvements and congestion relief that the finished project will bring to users of the interchange."
The rotary is located at Exit 46 on I-93 and is used by drivers heading to Methuen, Lawrence, Dracut and Lowell.
DiZoglio said the new interchange design will help prevent on- and off-ramp traffic from backing up onto I-93. The project is also expected to spark development along the Route 110 corridor.
A need for the project was first mentioned in an I-93 corridor study conducted by the MVPC in 2001. From 2007 to 2009, 650 accidents were recorded in or near the rotary — or more than double the amount of crashes in any other location in the area.