Kennewick considers bridge for Ridgeline Drive at Highway 395

The city of Kennewick is abandoning plans for a roundabout at Highway 395 and Ridgeline Drive in favor of a four-lane bridge.

City and state Department of Transportation staff had been at odds over plans for the intersection in Kennewick’s Southridge area.

Cary Roe, public works director, told the city council at Tuesday’s meeting that the city and state have come up with several options they can agree on, all of which would involve a bridge over Highway 395.

There is limited access now between Highway 395 and Ridgeline Drive. Drivers can’t turn left from Ridgeline Drive onto Highway 395.

Providing full access is key for the continued growth and development in the Southridge area and along the Highway 395 corridor, Roe said.

City staff had argued for a roundabout at Highway 395 and Ridgeline in 2013, but Roe, who joined the city last year, said state staff had legitimate safety concerns with the 60 mph speed, the 5 percent down slope and frequent truck use of the highway. About 30 percent of the traffic volume on Highway 395 is truck traffic.

Instead, state staff had supported a roundabout on a bridge over Highway 395, he said.

“We are fond of roundabouts here,” Roe joked.

The city agreed to back away from the roundabout idea and the Department of Transportation agreed to get the intersection among the top priorities in the region for a future statewide transportation package, Roe said. It’s unlikely to be funded this year, but the state Legislature might approve it within the next five years.

The preferred option appears to be a central turning option, tentatively priced at about $21.3 million, Roe said. The city council voiced general approval for that design.

A four-lane bridge would cross Highway 385 at Ridgeline Drive. One lane in each direction would go through to the other side of Highway 395. The other lane in each direction would be a turn lane to the on-ramps. There also would be a signal that would control control through traffic on Ridgeline Drive and left-hand turns on and off the highway ramps.

The on and off ramps to get from Ridgeline Drive to the freeway would connect to the left-hand lanes of Highway 395.

The design is not common, but Roe said the learning curve wouldn’t be large. There is a similar intersection on Interstate 5 in Federal Way that has functioned well.

Two other options were considered. One would have a loop ramp that would give more time to get up to speed to merge on the right-hand lane of Highway 395. That would use up more property next to the proposed intersection that otherwise could be developed.

The other would have drivers exit and enter on the right-hand lane of Highway 395. It also would use up more property than the preferred option.

Costs for all three options are fairly similar, Roe said.

Councilman John Trumbo said it’s important to preserve as much land as possible for development.

Roe said city staff has already begun reaching out to developers about the proposal. Initial feedback has been positive.

The city has a $750,000 federal grant to start the design of the intersection, Roe said. The Department of Transportation would like to design the project. The department has final say on what changes can happen on the state highway, Roe said.

Eventually, the city will need to ask the state to consider lowering the speed limit because the highway corridor is becoming more urban, Roe said. He’d like to see the speed limit at 45 mph.

This story was originally published January 27, 2015 at 8:33 PM with the headline "Kennewick considers bridge for Ridgeline Drive at Highway 395."