The Idaho Transportation Department has quietly announced it wants to tear down Rainbow Bridge, one of Idaho's most recognizable landmarks. ITD tucked this proposal inside an online feedback site without making a public announcement about the decision.
Highway 55 Construction History
Rainbow Bridge spans the North Fork of the Payette River on Highway 55, serving as the gateway to Valley County and McCall. The 1933 concrete arch bridge sits at the heart of a massive highway reconstruction project that has stretched for years.
ITD's work on this stretch began with widening the road between the bridge and Smiths Ferry. That project took years longer than expected and cost tens of millions more than budgeted, with landslides closing roads for weeks during construction. As BoiseDev reported in their original coverage, ITD initially studied rerouting Highway 55 away from the canyon entirely, but claimed it would cost more.
ITD's About-Face on the Bridge
Last year, ITD told the public it could keep Rainbow Bridge as a pedestrian overlook while building a new bridge for traffic. The department said it would study what keeping the bridge would require.
Now ITD has reversed course. "Our conclusion is that the best course of action is to suggest the removal of this bridge," said Jason Brinkman, ITD District Engineer, as reported by Boise State Public Radio on July 29. ITD claims extensive deterioration exists in the concrete and that keeping the bridge would cost between $20.3 million and $50.4 million - with no safe access for cars or pedestrians.
Design Options and Public Input
As for new designs, ITD has put forward nine bridge designs for public review. They range from simple steel structures to more classical arch designs that echo the original Rainbow Bridge's design.
Simple Steel Designs:
Haunched Steel Girder - A straightforward beam bridge design
Image from ITD Rainbow Bridge Online Meeting
Arch-Style Options:
Four-Spandrel Deck Arch designs in three variations: I-shaped steel, hollow box steel, and solid box concrete
Image from ITD Rainbow Bridge Online Meeting 
Image from ITD Rainbow Bridge Online Meeting 
Image from ITD Rainbow Bridge Online Meeting Multi-Spandrel Art Deco Arch - Featuring decorative elements reminiscent of 1930s architecture
Steel Thru-Arch - Where the roadway passes through the arch structure
Image from ITD Rainbow Bridge Online Meeting
Spandrel Braced Steel Arch - With diagonal support elements
Image from ITD Rainbow Bridge Online Meeting
Inclined Steel Arch - Featuring angled arch elements
Image from ITD Rainbow Bridge Online Meeting
Single Rib Concrete Arch - A minimalist concrete arch design
Image from ITD Rainbow Bridge Online Meeting
ITD also offers three retaining wall finish options: natural concrete, paneled concrete, and stacked stone appearance. The new bridge will sit slightly west of the current bridge with wider lanes and shoulders, supported by retaining walls up to 40 feet high.
Idahoans can comment on ITD's proposal until August 5 at their online site. Construction would begin in 2028.
Protecting Idaho's Architectural Heritage
ITD deserves credit for improving our roadways cost-effectively. But Rainbow Bridge isn't just infrastructure - it's an icon, listed on the National Register of Historic Places, and the largest single-span arch in Idaho. The bridge represents an era when we built things to last and inspire rather than the sterile, anti-human, post-modern designs that have come to dominate modern construction.
We should preserve this landmark or ensure its replacement honors the original's beauty and craftsmanship, rather than accept another bland, utilitarian structure.