I-90, ID-41 Interchange

The new interchange was designed to accommodate future traffic demands and to be compatible with other regional plans.

Future growth was modeled by pulling data from several sources, including: employment rates from the Department of Labor, structure data from Kootenai County, the 2010 national census, planned transportation projects and land use development as projected by cities in Kootenai County. Modeling supports the current design’s compatibility with expansion of ID-41 to three lanes and expansion of I-90 to six lanes. The base model was provided by Kootenai Metropolitan Planning Organization and used by the design team to evaluate how the project will perform with existing and future conditions.

Although not included in this project, ITD is seeking grant funds to relocate the Port of Entry to Huetter to minimize safety concerns posed by commercial traffic heading east through the interchange and up the grade.

Existing interchanges in Post Falls are too close together to allow the construction of additional interchanges. Current standards call for interchanges to be spaced at least one mile apart to reduce conflicts between traffic merging onto the freeway and other traffic weaving to exit. As it is, there are no other city routes capable of handling traffic accessing the interstate.

There are no other plans to modify interchanges in Post Falls, though transportation plans have long identified the need for an additional north-south route at Huetter to relieve pressure on ID-41 and US-95. The design of the ID-41 interchange will allow for ramps at Huetter, but at this time there is no funding to expand that route.

ITD is considering a combination of tunnels, overpasses and crosswalks to safely move pedestrians and bicyclists through the interchange. Both costs and benefits will be evaluated, with more details shared at the next open house.

Redesigning the interchange is expected to take at least two years. Any lane closures on I-90 will be scheduled at night, though drivers should expect congestion at other interchanges in Post Falls.

ITD is in the process of identifying staging plans for construction, which will detail detour routes and could include changes to the signal timing at other on-and-off ramps to handle extra traffic. The design team, which includes the City of Post Falls and Kootenai County, will present options to minimize ramp closures and maintain mobility at the next open house in the spring. Options will not include the construction of other ramps as existing ramps do not have enough room between them to make this safe.

Although the ramp will only be striped for one lane, it will have wide shoulders to keep traffic moving around most crashes as well as to provide room for staging during construction and future maintenance operations. ITD will also use signage to redirect traffic around crashes at that ramp, as it does now by changing messages at signs located near the state line. Another digital emergency sign will be placed on eastbound I-90 near Greensferry with this project.

Modeling shows that once constructed the new interchange will be safer, more efficient and easier to navigate while being compatible with future expansion of ID-41 and I-90.

Access to businesses on ID-41 north of the interchange will remain the same, though a new median barrier will not allow left turns onto or from the highway. Access will continue to be provided primarily through side streets or signalized intersections to improve traffic flow and make it safer.

Most local roads will continue to function the same as they do now, though access to the freeway south of the interchange will be simplified. Ross Point Road will be restriped to accommodate additional street parking. Other changes to traffic control, speed limited and parking may take place after construction by the city as modifications are not supported by traffic modeling.