Borrowing a page from Kennewick's playbook, Richland is eyeing roundabouts to control an expected spike in traffic on part of Duportail Street.
Late next year or in early 2016, Richland will extend Duportail to Wellsian Way and eventually link it across the Yakima River.
Once the Wellsian Way extension is complete, rush hour traffic on Duportail through Thayer Drive is expected to jump from 53 vehicles to more than 400, according to a report released in mid-September by Spokane-based David Evans and Associates.
Rush-hour Duportail traffic at the Wright Avenue intersection could swell from 269 vehicles to 407.
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The report recommends the city install roundabouts at the two intersections to best control the expected commuter traffic.
Richland is home to several traffic circles and one true roundabout, which sits at the Columbia Park Trail-Steptoe-Highway 240 intersection. That one was built by the state Department of Transportation.
By comparison, Kennewick has 21 roundabouts.
Revamping and extending Duportail Street to Wellsian Way should cost about $3.7 million, said Pete Rogalsky, Richland's public works director.
State and federal money will pay for the bulk of the work. The project still requires the city to buy some right-of-way property.
The traffic analysis report looked at numerous traffic-control measures for the two Duportail intersections. It also examined installing stoplights, creating four-way stops instead of the current two-way stops, reversing the current two-way stops to allow continuous travel on Duportail Street or leaving the intersections as they are. The existing two-way stops halt Duportail Street traffic.
The report concluded that the intersections do not have enough traffic to warrant signals. Four-way stops could have been used as a transition to a signal, but now won't likely be considered, Rogalsky said.
Longer term, a separately funded, but related project calls for a four-lane bridge to connect the north and south sections of Duportail across the Yakima River.
The planned bridge, part of Richland's 2018 capital improvement plan, would provide a more-direct connection between central Richland and the booming Queensgate area on the city's south end.
The bridge should also improve fire department response times after a fire station is built near the Duportail-Queensgate intersection in June 2015.
"The (station's) full impact won't be felt until the bridge is built," Rogalsky said.
The bridge is estimated to cost about $35 million. No construction timeline has been set.
"We really don't have construction funding established or collected to build it," Rogalsky said. "So until we have that funding, we can't put a timeline on it."
About $3 million has been spent on the bridge project to buy rights of way, perform environmental reviews and create a preliminary design. The city plans to approach the state Legislature next year to find more money, Rogalsky said.
He said the city is still working on a timeline for the other Duportail Street work, including the addition of sidewalks and bike lanes.
An open house is planned this month to solicit ideas on the intersection design, parking and bike lanes. City officials will present intersection alternatives and share results of the traffic study.
A meeting date has not been set.
The bridge project also includes an extension of Tanglewood Drive in both directions along the Yakima River, as well as a traffic signal at the intersection of Duportail and Tanglewood. Those costs are included in the $35 million price tag.
A water supply pipeline buried beneath the river near the site of the planned Duportail bridge would be replaced as well.
Erosion has exposed the decades-old line, Rogalsky said.
The new line would be attached to the bridge's underside and run above the river.
A $2 million Federal Emergency Management Agency grant will pay for the majority of that estimated $2.6 million project.
-- Drew Foster: 509-582-1513; email@example.com