Description
The Washington State Department of Transportation intends to make state Route 18 safer and increase capacity and efficiency, as the volume of vehicles traveling the highway between Auburn and Interstate 90 continues to increase.
WSDOT is transforming the roadway in segments, with safety improvements initiated in the early 1990s. The Maple Valley to Issaquah Hobart Road project continues the effort to widen the highway between Auburn and I-90.
Atkinson Construction is widening a 3-mile section of the two-lane highway between the Cedar River in Maple Valley and Issaquah Hobart Road to four lanes. The project’s design has a 48-foot-wide grassy median as a safety barrier between the two lanes of traffic traveling in opposite directions.
The additional highway lanes and interchanges are critical for managing increasing traffic volume. Growth models predict by 2010 the existing two-lane highway would suffer seven hours of traffic congestion each day. Widening the road, as well as constructing interchanges and bridges, will contain congestion to only one hour per day.
According to WSDOT models, the improvements equate to a projected average afternoon traffic speed of 59 mph in the year 2010, compared to 18 mph without the work. After this project is completed, the outlook for the year 2020 predicts little additional traffic congestion.
In order to reduce hazards of turning onto and off of Route 18 from side roads, the project includes several new interchanges. The signalized, at-grade intersection at 244th Avenue Southeast will be replaced with a new interchange. At-grade intersections will be eliminated at Southeast 236th Street and at Southeast 200th Street.
Plans also call for building a new bridge to cross over Route 18 at Southeast 200th Street.
Additionally, work will improve local access with a new frontage road between Maxwell Road and Southeast 236th Street.
Sensitive areas in the vicinity required advance planning and concern. Some of the steps taken to minimize environmental impacts included creation, enhancement and purchase of wetlands; stream realignment; and replacing culverts with bridges to improve fish passage.
In total, the project includes building 15 bridges and 48 retaining walls.
After work on the Maple Valley to Issaquah Hobart Road section of Route 18 is completed, there are still seven miles of Route 18 to be widened from Issaquah Hobart Road to I-90. The remaining stretch of work is under design and still requires funding as one or more separate projects.
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Contractor:
Guy F. Atkinson Construction, P.O. Box 940, 600
Naches Ave. S.W., Suite 120, Renton, WA 98055-2267,
(425) 255-7551
Engineers:
Dave Standahl (construction project engineer), WSDOT
Maple Valley Project Office, 26157 Maple Valley Black
Diamond Road, Maple Valley, WA 98038-8353,
(425) 433-2002.
Gary L. McKee (design project engineer), WSDOT Corson
Project Office, 6431 Corson Ave. S., Seattle, WA 98108
1310,
(206) 768-5761
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Other Participants
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ACC Hurlen Construction
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Concrete Technology Corp.
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Condon-Johnson & Associates
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D.S. Brown Co.
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DS Purcell Painting
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F & H Fence Co.
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Glacier Northwest
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Harris Rebar
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INCA Engineers
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John-Wayne Construction
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KLB Construction
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Lakeside Industries
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Novito Construction
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Petersen Brothers
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Rainier Steel
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Ralph’s Concrete Pumping
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Skyline Steel Corp.
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Specialized Pavement Markings
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Terra Dynamics
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Totem Electric of Tacoma
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