Reconstruction of a worn and unstable section of the West Valley Highway in Auburn is well under way. Crews are busy restoring the well-used highway, from the foundation up.

The highway project, estimated at $4 million, is about 16 years in coming, Mayor Pete Lewis said. The City’s wait ended when the Washington State Transportation Improvement Board awarded a grant this year.

The section of the two-lane highway from State Route 18 to West Main Street will be closed until approximately Oct. 21 to allow for the upgrade of a new, expanded and safer roadway.

The intersection at West Valley Highway and West Main Street will remain open during the reconstruction period to accommodate business and the delayed flow of detoured traffic. But the intersection will be subject to intermittent lane restrictions and closures.

West Main, C Street Southwest and 15th Street Southwest will be signed detour routes.

Construction, weather dependent, is expected to continue until the end of the year, project coordinators said.

The highway is expected to reopen after Oct. 21, but reconstruction will continue and motorists can expect delays. Motorists are advised to avoid the area.

Significant rainfall and runoff from the hillside essentially have made the road unstable, according to Jacob Sweeting, a project manager and engineer for the City of Auburn Public Works Department.

The worn roadway surface is prone to cracks, potholes, wheel ruts and damage caused by surface drainage and groundwater seepage, City officials said.

The City’s plans call for rebuilding and widening the 1,870-foot section of West Valley Highway South from Highway 18 to West Main Street, and will include bicycle lanes, sidewalk, lighting, improved drainage, a center median and extended turn lanes.

The intersection of West Main State and West Valley Highway also will be improved with a new signal system. Trucks and large vehicles periodically have hit the signal poles at the intersection corners. New poles will be set back from the corners that will be widened to accommodate turning vehicles.

Highway improvements were needed to improve traffic flow.

During peak traffic times, northbound traffic backs up at the signal near the SR 18 overpass and blocks the turn pocket that serves traffic turning east onto the eastbound SR 18 onramp. The City has determined that the congestion and delays can be alleviated by extending turn pocket lengths and adding a center median.