Traffic volumes on Interstate 90 and Idaho Highway 41 continue to grow, prompting the redesign of the interchange to safely accommodate more drivers.
The interchange will be redesigned to enhance safety and capacity. Depending on the new design, that could involve replacing bridges, realigning on- and off-ramps, providing continued access for cyclists and pedestrians, and constructing capacity for planned and possible expansion. As the project develops with public input, other considerations--such as the existing at-grade railroad crossing, synchronization of signals, barriers between lanes, the proximity of the Huetter rest area, and the grade of the interstate--may be addressed as well.Read More
The team developed this design after the public meeting and property owner contacts in November 2018. As an offset single-point urban interchange (SPUI), it merges the advantages of both the half-diamond interchange and the SPUI previously proposed.
With this design, ID-41 would still shift to the west and pass under I-90. All ramps will meet at a single point just north of the interstate. Eastbound ramps will pass underneath the interstate to connect with the highway. The westbound off-ramp will no longer be a loop ramp and will be elongated to meet current standards.
Because the interchange will be shifted north, there will be fewer impacts to the local system. The signal currently controlling the Ross Point Road, Seltice Way, ID-41 and I-90 intersection will be removed and replaced with a stop sign at Ross Point Road. After being shifted, the highway will connect with Seltice Way at Herborn Place and be controlled with a signal. ITD will continue to work with the city of Post Falls to finalize the design.
After construction, the Centennial Trail will likely pass underneath the interstate and continue north. A connection to the neighborhood south of Seltice Way will be constructed.
By using one signal, rather than two signals to control movements, the SPUI design will likely be more efficient and decrease travel times at this busy intersection.
This design will achieve the efficiencies of a SPUI interchange with excellent compatibility with future expansion for an estimated $39 million.
Engineers began collecting data to assess the needs of the project, ranging from traffic volumes to stakeholder identification, to develop various interchange designs.
ITD met with the city, planners and engineering firms to assess the needs of the project before creatively and collaboratively identifying solutions. Nine alternatives were explored by the group, and the department has selected two alternatives to present to the public at the meeting in early November.
ITD is continuing coordination with local jurisdictions, and after evaluating public comments submitted after the open house, will select an alternative--whether it be the single-point urban interchange or the half-diamond interchange--to pursue. The decision will likely be made before 2019.
After receiving public feedback and continued discussions with the city of Post Falls, ITD has selected a new design to improve safety and capacity at the interchange. Called an offset SPUI, the latest design eliminates the loop ramp, reduces impacts to Seltice Way and achieves the efficiencies of a single-point urban interchange at a lower cost. Read more about this decision.
ITD will continue to develop details for the final design and construction.