UNION GAP, Wash. -- On a daily average, 3,400 trucks hauling freight travel along Main Street and Valley Mall Boulevard in Union Gap just to access Interstate 82.

But the route, city officials say, is a recipe for disaster with Valley Mall and other shopping centers nearby. Large 18-wheeler trucks often are forced to mix with commuters and shoppers through a series of roundabouts that form the Valley Mall Boulevard and I-82 interchange.

“Trucks and commercial traffic just aren’t a good match with the mall and everything in there,” said Union Gap Public Works Director Dennis Henne. “We just need to separate our freight traffic from our commuter and commercial traffic.”

That’s the objective of two planned projects — the Regional Beltway Connector and the South Union Gap Interchange — that will establish a new route to I-82 at the south end of the city.

Union Gap has teamed with the state Department of Transportation on the projects that cost $52.3 million combined.

City and DOT officials on Tuesday will unveil details of the projects during a 4 p.m. public meeting at the Union Gap Activity Building.

Teaming with DOT, the city plans to link Ahtanum, Goodman and Longfibre roads to a single connector to I-82 and nearby U.S. Highway 97. The configuration bypasses Main Street.

While the city’s $17.9 million project — the Regional Beltway Connector — focuses on Ahtanum, Goodman and Longfibre roads, the DOT’s $34.4 million project — the South Union Gap Interchange — will construct new ramps allowing traffic to enter and exit the interstate in both directions.

Currently, there is only a partial interchange at the south end of Main Street, with one westbound offramp and one eastbound onramp to I-82.

The partial interchange was built in 1979, and present DOT officials couldn’t immediately provide the reasoning behind the initial interchange design.

The DOT project is being funded out of the state’s $15 billion transportation package. Construction is expected to begin in spring 2019 and be completed in the fall of that year, DOT officials said.

Union Gap has already spent $3.65 million to complete the first phase of its project, which included extending Longfibre Road south to a roundabout that connects to Goodman Road and building a bridge over Ahtanum Creek. Another road will extend from the roundabout eastward and connect to the new I-82 interchange and U.S. 97.

Construction on the rest of the project won’t begin for about three years, Henne said.

It will take the city that long to acquire additional funding, environmental permits and needed right of way, he said.

However, the city recently received a nearly $2 million federal highway grant that will cover the cost of the remaining planning work — now the city needs only to raise construction money, he said.

Construction costs aren’t as hard to get once the planning is done, he said.

Several years ago, Union Gap managed to garner grants to cover the $12 million cost of the Valley Mall Boulevard interchange, a project that quickly came together once the planning was complete, he said.

Once this project is complete, traffic congestion at the Valley Mall Boulevard interchange will drastically reduce, improving safety, Henne said.

“We’re getting the freight out of our downtown core,” he said. “It gets the trucks out of our commercial areas and our downtown areas, so a lot of it is for freight movement and safety concerns.”

• Phil Ferolito can be reached at 509-577-7749 or pferolito@yakimaherald.com. Follow him on Twitter at philipferolito@twitter.com.