US 95/ID 53 Garwood Road Improvements Bring Greater Capacity to Growing Area
Increased Safety and Mobility: Idaho Transportation Department Improves the US 95 Corridor from Coeur d'Alene to Sagle
The state of Idaho is one of the fastest growing states in America. From 2010 to 2018, the population of the western state grew by almost 12 percent while the state capital, Boise, grew by 18.5 percent. Reasons experts give for the state’s rapid growth vary – low taxes, natural beauty, growing tech scene – but the details are not important when it comes to infrastructure. To help traffic move more safely and efficiently on a local and regional level, the Idaho Transportation Department (ITD) is engaged in the U.S. 95/ID 53 Garwood Road project.
This project grew out of a 2010 corridor study and it’s part of an effort to improve the entire corridor of U.S. 95 from Coeur d'Alene to Sagle. The two north central Idaho cities are approximately 40 miles apart.
There are several key elements of the project. These include the removal of two signalized intersections and replacing them with an interchange and an overpass. “We want to get rid of the stoplights because it will increase safety and mobility in the corridor,” says Joey Sprague, a Staff Engineer for ITD who is serving as the Project Manager. Once the signals are removed, the speed limit will be increased on the road from 55 mph to 70 mph.
A railroad bridge is being removed and replaced with a new one. The current bridge is dated, narrow and part of a hairpin corner. “We’re realigning the highway – widening it – and putting in a new bridge, which will improve the safety of that stretch of highway,” says Sprague.
The team is also extending frontage roads on the east and west side of U.S. 95. The frontage roads will help consolidate access on this highway, only allowing traffic to access U.S. 95 where safety elements, like turn bays, lighting, ramps, etc., have been constructed. This will serve as the template for the corridor to reduce high-speed collisions that result in serious injuries or deaths.
The corridor’s design also includes accommodating other forms of transportation. Last fall, 8 miles of the existing trail in the Coeur d’Alene area were repaved and another 9 miles of new path were paved. The newly extended path will tie into an existing path from Athol to Farragut State Park.
Diamonds may be a girl’s best friend, according to the old saying, but a traditional diamond interchange was not right for this project.
Instead, ITD is going with a Single-Point Urban Interchange, or SPUI as Sprague and his colleagues affectionately refer to it. A SPUI has one signal that controls all of the interchange traffic.
“There are no SPUI’s in North Idaho, so there’s a learning curve for commuters about how to get through it,” says Sprague. ITD has made videos for users to access and learn more about SPUI’s.
As to why they bucked tradition and went with the SPUI, Sprague says, “It was mainly based on geography. The traditional diamond interchanges would not fit into the space as there’s a rock wall nearby.”
A SPUI interchange is also a practical choice because they are more efficient. A SPUI improves traffic functionality of an interchange as a whole – certain movements that had to run separately can now run together, saving time. Drivers, depending on their destination, will also only wait at one signal, rather than the two included in the traditional diamond interchange.
Another unique or challenging aspect of the project arose with traffic control. “When we started detouring at the beginning of the project, there were two intersections close to each other that bogged down,” says Sprague. Various options were implemented to speed things up. “We worked with Idaho State Police to figure out the best way to get cars through the intersection and it’s working much better now.” He notes it also helps that drivers have adjusted to the detour, with locals tending to find their own routes, reducing congestion on the designated corridor.
Schedule and Budget
Phase one of the project, which includes the construction of the interchange at U.S. 95 and ID 53, began in the summer of 2019 and is expected to be complete this fall. Phase two of the project, which includes an overpass at Garwood Road, is set to start this summer and go to the fall of 2021.
Sprague notes that the project is mostly on schedule so far. “We’ve had some challenges in staying on schedule due to the project’s proximity to the railroad, which naturally includes more coordination and approvals,” says Sprague. Some adjustments were made to the schedule, and as a whole the project is on track. Sprague credits the contractor for keeping the project moving forward, “The contractor on phase one has been very focused on getting the project done quickly and at top quality.”
Construction of the U.S. 95/ID 53 Garwood Road project is budgeted for $32 million. It’s on budget so far. “This project was designed very well,” says Sprague. “There’s been very little need for changes as a result of the quality of the design.” He notes that construction has gone smoothly, and the team has yet to run into anything unforeseen.
The sudden popularity of Idaho and growth of the state’s population has left Idahoans dealing with changes, including more traffic. The U.S. 95/ID 53 Garwood Road project will help commuters handle the traffic load and increase safety and efficiency. It’ll be a boon for all of Northern Idaho.