Heading south on Highway 395? You’ll need to take this detour in Tri-Cities

A year-long detour on Highway 395 — the main southern entrance and exit to Kennewick — started this week as road crews began work on a bridge under the interstate.

Construction on a $13 million underpass to reroute Ridgeline Drive under Highway 395/Interstate 82 started in the spring.

But now traffic will need to be diverted to a detour route east of Highway 395, with one northbound lane, two southbound lanes and a median barrier.

The route with a 40-mph speed limit will remain in place until work being managed by the Washington State Department of Transportation is complete in Fall 2022.

Extensive growth in housing and businesses in the Southridge area of Kennewick has caused the area to have increased congestion — and development is continuing. The area is south of Trios Southridge Hospital and Southridge High School.

The project will add on- and off-ramps from the highway, making it possible to head left at the Ridgeline interchange.

That’s also expected to relieve the congestion at the Hildebrand Boulevard intersection to the north.

The project received $15 million through Connecting Washington, the 2015 Legislature’s transportation package.

The same package put money toward Richland’s now-completed Duportail Bridge and Pasco’s Lewis Street overpass. Construction on that project is just getting under way.

Kennewick plans to extend South Zintel Way from Ridgeline Drive to West 40th Avenue. The extension will include a roundabout at Zintel and Ridgeline.

A new water line also will be installed with the underpass.