Work will begin in April on a $16 million, two-year project that will complete major improvements to Rainier Avenue South between Grady Way and Third Avenue South in Renton.

Local, county and state officials gathered Tuesday to ceremonially break ground on the project in the parking lot of McLendon Hardware on Rainier Avenue. It’s the continuation of State Route 167 into Renton.

Rainier carries thousands of vehicles through central Renton every day, as a major north-south corridor that links South King County to south Seattle.

The project will improve transit mobility, upgrade traffic safety, and enhance pedestrian safety with new eight-foot wide sidewalks, landscaped buffers and improved street lighting.

In earlier phases, the City of Renton and its construction partners, including Sound Transit, Metro Transit and Burlington Northern Santa Fe Railway, removed the railroad bridge over Rainier Avenue and replaced the “cow bridge” under the tracks on Shattuck Avenue.

In all the Rainier project will cost about $42 million, paid for with local, county, state and federal dollars.

“This is one of the major commercial corridors in Renton,” said Mayor Denis Law at the groundbreaking. “Improvements here will provide significant benefits to businesses, enhance the economic vitality of our downtown, and strengthen transportation in and through Renton.”

Five lanes of traffic will remain open during construction, with access maintained to businesses on both sides of Rainier. Extensive night work is planned, when construction could block that access.

Signs along Rainier will direct motorists to driveways for local businesses.

The project will create normal construction delays, said city public works director Gregg Zimmerman, but “we are not predicting huge delays.” The city has not planned for a detour route as it did for earlier work.

“It’s our intention to keep all of the traffic on Rainier,” he said.

The city will set up a hotline where complaints about construction noise can be lodged.

The general contractor will update the city’s website with the latest information about the project and will provide public relations, he said.The city is putting “a lot of effort” into communications because Rainier is a major commercial and transportation corridor, he said.

“We are excited about the improvements to come and appreciate the support and dedication of the elected officials who have worked towards completion of this project for many years,” said Gail McLendon, president of McLendon Hardware, said Tuesday.

Johansen Excavating of Buckley is the project’s general contractor. It had submitted the second-lowest bid; however, low bidder, Bellevue-based Tri-State Construction, dropped out of the project after it could not obtain a performance bond, according to Zimmerman.

The Johansen bid is about $160,000 higher than Tri-State’s, he said.

A performance bond ensures that the city would have access to money to complete a project if the general contractor leaves the project partially complete, Zimmerman said.

This will be the first time that the city has worked with Johansen on a road project. However, Zimmerman said, the city’s management consultant on the project is familiar with Johansen from a similar project on State Route 99 in the Shoreline area, he said.

The city doesn’t yet have Johansen’s construction schedule, but it’s the city’s understanding the company will start work in April, he said.

This final phase of the Rainier project will be paid for with funds from the City of Renton, Sound Transit, U.S. Department of Transportation Federal Highway Administration, Transportation Improvement Board, Washington State Department of Transportation, Puget Sound Regional Council, and the Department of Commerce Public Works Board.

“Sound Transit’s major investment in this project will help move buses and pedestrians more quickly through the corridor, making connections to Sounder commuter rail and King County Metro Transit’s RapidRide more accessible and convenient,” said Sound Transit Board Chair and King County Council member Julia Patterson.

“Our contribution to this project exemplifies the importance of regional partnerships in improving transit for Central Puget Sound residents,” she said.