ST. MARIES — An $18 million, three-month construction project to widen 3 miles of Highway 3 is scheduled to begin later this month.

But prior to that, on Monday, the Idaho Transportation Department will improve Goosehaven Road by adding more material and then leveling the route so it may serve as a detour for Highway 3, which will be closed.

“Drivers should prepare for delays on Goosehaven Road but not on SH-3,” Project Manager Matt Heinichen said. “We will also apply material to minimize dust created while traffic uses the detour.”

Plans call for the highway to be widened by 11 feet to the east, making room for 11-foot travel lanes and 3-foot shoulders. Guardrail will be installed along the east side.

ITD has provided Benewah County Road and Bridge with materials to widen Goosehaven Road to prepare it for highway traffic. The road will only be widened, not paved.

“Closing the highway completely will allow us to expedite construction,” Heinichen said. “We have been working with the county to minimize impacts, and this detour is critical to getting the work done.”

According to ITD, previous projects to widen a longer section of highway stalled due to environmental challenges.

“Traditionally, highways are expanded by importing embankment material, but in this case, the extra weight would collapse the soft soils and cause settlement problems for the highway,” ITD said. “It would also require the department to buy more property and likely cause significant wetland and cultural impacts.”

To get the extra width, crews will use a specialized, lightweight product known as geofoam. This will allow expansion without adding weight, ITD said. It also won’t require more land to be bought, minimize utility moves and avoid wetland/culture impacts.

Funding for design of the latest project was approved by the Idaho Transportation Board in April 2020 for $1.5 million.

In May 2021, the board allocated $18 million for construction. The funds come from money ITD held back in spring of 2020 in anticipation of reduced gas tax revenue during the COVID-19 pandemic.

In other ITD projects, several bridges in the Coeur d’Alene area will be repaired this summer, with work beginning first on the U.S.-95 bridge over Northwest Boulevard.

Construction started April 4, to paint the steel railing and replace the surface of the U.S.-95 structure. During the two months of work, southbound drivers will not be able to use the left turn lane on the bridge to access downtown via Northwest Boulevard.

As part of this project, other bridges will also be improved this season:

In early May, crews will close one lane of the bridge on Potlatch Hill Road where it crosses over Coeur d’Alene Lake Drive and provides access to the Terraces at Lake Coeur d’Alene. Temporary signals will be in place for one month to control one lane of traffic.

Starting in June, Seventh Street over I-90 will close, and traffic will be detoured to Ninth Street for one month.

Starting in early July, the bridge on I-90 over Wolf Lodge Creek will be sealed to prevent damage from weather. Crews will close one lane in each direction for one month.

Starting in late July, crews will close one lane in each direction on the Greensferry Road overpass in Post Falls for a few days as they work on joints that allow the bridge to expand and contract with the weather.

Later this summer, a different project will also address repairs to another six bridges in the Coeur d’Alene area, including the Spokane River Bridge on U.S.-95.