Project begins on U.S. 95 Lewiston Hill May 18

A deep pavement rehabilitation will begin May 18 on the U.S. 95 Lewiston Hill, affecting both the north- and southbound lanes through the project’s expected completion in early September. This section of road carries more than 10,000 vehicles per day.

The highway in this five-mile section is in poor condition, which has resulted in many potholes in the driving surface. This pavement rehabilitation is expected to extend the life of the road by about 20 years.

Beginning at the sign bridge at milepost 312.5 and ending at the approach to the Old Spiral Highway at milepost 317.4, crews will grind off up to 6.5 inches of the roadway depth and repave with hot mix asphalt to match the existing super-elevation and grade of the hill.  Then, a three-inch asphalt pavement overlay will be placed over both the northbound and southbound lanes.

The contractor is proposing to use a recycled asphalt pavement process, which will reduce the amount of new asphalt and aggregates required.  The ramps at the interchange at the bottom of the hill also will receive a two-inch overlay. At the top of the hill, the route will be resurfaced using a CRABS (Cement Recycled Asphalt Base Stabilization) process and an overlay.

The median concrete barrier will be removed and replaced with new concrete barriers that meet current safety standards. The metal guardrail and terminal sections also will be replaced to meet current safety standards. All crash cushions within the construction limits will be replaced.

Numerous maintenance projects have been performed in the past on the original pavement, placed in 1976. These have included overlays, plantmix seals and seal coats. However, these surface treatments have proven insufficient to keep the highway in good condition.

An advisory 45-mph speed limit will be used to control traffic speed. Four 11-foot-wide lanes will remain open for a majority of the work. The locations of these lanes will change as work on the hill progresses. Traffic revisions should be expected every week. Electronic signs will be used to alert drivers to these changes.

Knife River Corporation, Boise, is the contractor on the $11.5 million project.

To minimize the impact to drivers, the contractor will use a six-day workweek, Monday through Saturday, 20 hours per day, to complete this project as quickly as possible.


Published 05-08-15