11/16/2022
John Tomlinson
ITD Communication Manager
208-501-5671
john.tomlinson@itd.idaho.gov
Construction on State Highway 55 at Smiths Ferry pauses for winter season
SMITHS FERRY, Idaho – Construction on State Highway 55 near Smiths Ferry, 46 miles north of Boise, has reached a major milestone as construction work pauses for the winter season. Road paving and major slope excavation are now complete with two lanes open for travel.
In fall 2020, the Idaho Transportation Department (ITD) started construction on the project to widen the highway, straighten the road alignment, and add guard rail along a curvy one-mile stretch of SH-55 between Smiths Ferry and the Rainbow Bridge. These important safety improvements are now finished.
The challenging project took place in rugged terrain with a narrow work zone in the North Fork of the Payette River Canyon. Months of drilling, rock blasting, excavation, and other work have resulted in a new safer highway alignment with mesh and catch ditches to mitigate rock fall, vehicle pullouts, a retaining wall along the river, new guard rail and pavement, and wider shoulders on the highway. A large landslide during a SH-55 daytime closure in November 2021 led to changes in the engineering design and construction work to remove an additional 100,000 cubic yards of rock and soil this year.
Download photos of SH-55 here and here.
The project construction site will be closely monitored this winter with the snowpack, temperature, and forecasts checked regularly. If potential avalanche conditions based on these measurements are identified this winter, the road may be temporarily closed and drivers will be asked to use U.S. Highway 95 as an alternate route until the area is cleared. Project slope finishing work will continue next spring and summer of 2023 and include implementing avalanche mitigation snow fencing systems designed to minimize future risk.
Driving on Idaho’s mountainous roads comes with inherent risks of difficult winter driving conditions. Motorists are urged to be prepared and check 511.idaho.gov before traveling.