The Maine Department of Transportation’s $8.4 million River Road widening project has resumed for the year, with a goal of completion by early December.

River Road, which follows the Presumpscot River and is known for its twists and hills, is a major commuter byway linking North Windham with Westbrook. The 5.9-mile section under construction stretches from Route 202 in South Windham to Page Road in North Windham.

The project began last June, stopped in late January for a winter hiatus, resumed in mid-April, and is set to conclude by Dec. 4, according to Tim Kelley, a resident engineer for the Maine Department of Transportation. Last year, construction workers cleared trees and brush, constructed catch basins and driveway culverts, and installed new utility poles set farther back from the road, in order to enable the construction of new, 5-foot shoulders.

The department also hired contractors to convert a dangerous intersection at Windham Center Road into a roundabout. Since the four-way intersection of Windham Center Road and River Road, which was previously governed by one flashing light, has been the site of several serious car accidents, the state is managing an effort to turn the intersection into a 140-foot-diameter roundabout with 5-foot sidewalks on the perimeter, as well as crosswalks. The single-lane road in the roundabout is 16 feet wide, according to Ernie Martin, project manager for the state.

This year, contractors will complete the roundabout project by constructing sidewalks, installing granite curbs, putting down loam and adding landscaping features in the center of the island, according to Kelley. The prime contractor on the project is R.J. Grondin & Sons of Gorham, while Stillwater-based Dirigo Slipform is working on the sidewalks and granite work.

For the entire project, Kelley said, workers will spend much of the year flattening and stabilizing River Road with “cut and fills” and a “foamed asphalt” treatment, in which the existing road surface is pulverized and then injected with foamed asphalt cement. The goal is to make the road more easily navigable and improve visibility, he said. The recycling process is also less expensive than using all new material.

“Several areas will be and are being raised or lowered to allow for better visibility,” Kelley said. “The remainder of River Road will receive an in-place treatment called foamed asphalt.”

Workers will lay 3 inches of fresh pavement at the top of the road surface, Kelley said. The new River Road will feature 11-foot-wide lanes and 5-foot-wide shoulders, he said.

Kelley said the department has aimed to limit traffic delays to five minutes, with the exceptions of emergency work. Windham Town Manager Tony Plante said he has not heard much in the way of complaints, apart from concerns about dust being kicked up during the weekends.

“They’re going to be doubling their efforts to address that,” Plante said. “Once the paving is done, the dust problem goes away.”

Plante encouraged drivers in a hurry to avoid River Road.

“It’s going to be a long summer and if people are looking to avoid delays they should avoid River Road,” he said.

Richard Nicholson, a worker with the contractor Dirigo Slipform, measures the dimensions of a new sidewalk with co-worker Cliff Berry. Jim McKenney, a flagger with the firm Project Flagging, looks on. Work resumed at the new roundabout at the four-way intersection of Windham Center Road and River Road on April 20. Staff photo by Ezra SilkRichard Nicholson and Cliff Berry of Dirigo Slipform measure the dimensions of a new sidewalk at the intersection of Windham Center Road and River Road. A new roundabout has been constructed at the intersection.  Staff photo by Ezra Silk