UDOT lays out purpose and need for possible Spanish Fork I‑15 interchange; public comment open through Nov. 13

UDOT project manager Darren Bunker on Nov. 1 told the Utah County Board of Commissioners that a potential new interchange on I‑15 near Spanish Fork is intended to improve regional mobility, provide safe east‑west connectivity for all users and reduce congestion on Spanish Fork Main Street.

Bunker said the project team used the 2050 travel‑demand model and existing city plans to identify three primary needs: (1) improve regional mobility by giving commuters better access to I‑15; (2) provide multimodal east‑west crossings that accommodate cars, transit, cyclists and pedestrians; and (3) reduce growing congestion on Main Street. “The purpose of the interchange project is to improve safe and efficient access across I‑15 for all users in the Spanish Fork area and surrounding communities,” Bunker said.

Why it matters: UDOT’s traffic modeling shows long peak‑hour delays if no improvements are made. Bunker showed that, under a no‑build scenario, queues would back up at the US‑6 and 800 South interchanges and could extend onto I‑15. He cited an example where northbound peak travel from Volunteer Drive to I‑15 would increase from about 7.3 minutes to roughly 23.6 minutes by 2050 if no new interchange is built.

How alternatives will be chosen: UDOT described a staged screening process. Level 1 will test whether candidate concepts meet the stated purpose and need using travel‑demand and traffic‑simulation models; alternatives that fail to attract sufficient traffic away from existing interchanges or that do not improve Main Street traffic will be eliminated. If more than one alternative passes Level 1, Level 2 screening will apply NEPA requirements, evaluating environmental impacts including Waters of the U.S., relocations and Section 4(f) resources such as parks and historic properties. Bunker said alternatives with greater environmental or social impacts would be removed from consideration.

Public input and timeline: Bunker said an additional public comment period focused on the purpose and need is open through Nov. 13. The environmental document and a later public review will precede selection of a preferred alternative; a decision is anticipated in fall 2024.

Local response: Commissioners noted Spanish Fork’s prior efforts to preserve right‑of‑way and thanked UDOT for the proactive planning. County staff signaled willingness to continue public engagement and return with final findings.

Next steps: UDOT will continue the screening process, collect public input through Nov. 13 and proceed with environmental review. The county will receive further briefings as the project advances.