The Washington state Department of Transportation has awarded an $11.2 million contract to Harcon Inc., of Spokane, for construction of a new interchange at Interstate 90 and Evergreen Road, as well as other related work.


Regional DOT spokesman Al Gilson says a start date for the big interchange project will be set at a preconstruction conference scheduled for this week. The project is expected to get under way sometime this fall and will take about three years to complete.


In addition to constructing the new interchange, which will have on-ramps and off-ramps for both eastbound and westbound I-90 traffic and a seven-lane bridge that will carry Evergreen over I-90, the project will add an additional freeway lane in each direction between Pines and Sullivan roads.


Also, Evergreen will be redirected and widened to six lanes from about where Sinto Avenue would intersect with it, south of the freeway, all the way to Indiana Avenue, on the north side of the freeway. As that new roadway heads north toward the freeway, it will run beneath another new bridge that will carry Mission Avenue over it, then drop sharply down a hill to where it will be carried over the freeway at the new interchange. Another new roadway will be built to allow traffic to flow between Mission and the new portion of Evergreen.


Also as part of the project, a current section of Evergreen between Boone Avenue and the southern end of the new section of Evergreen, at about Sinto, will be widened to six lanes.


Other minor work related to the construction of the interchange will include the realignment of Nora Avenue, which is directly south of the interstate, between the Pines interchange and Mamer Road, and some repaving on the westbound ramps at the Sullivan interchange.


Spokane County plans separate projects in the next two years to improve both Evergreen, from Boone south to Sprague Avenue, and Mission, between Sullivan and McDonald roads, to handle increased traffic expected as a result of the new interchange.