Jefferson County commissioners adopted a transportation plan for the east side of Interstate 15 on June 2 but added a formal caveat directing staff to expand traffic data collection and prepare a countywide update.

The plan before the board updates a document that county staff said dates back to 2007 and covers only the east side of I-15. Milton (planning staff) told the board the draft had been prepared in 2023 and that the Planning and Zoning Commission recommended additional changes, including a countywide traffic study. “The last transportation plan was ... put together back in 02/2007,” Milton said, and he described the current draft as limited in scope.

Why it matters: Commissioners and staff said the plan provides guidance for where the county should focus improvements and how to advise developers, but they agreed it is incomplete: it omits the west side of the county and relies on a relatively small study budget. Commissioners conditioned adoption on continuing work to expand traffic counts, update mileage totals and incorporate additional studies such as a BYU–Idaho analysis the planning commission recommended including.

Discussion and direction: Commissioners raised several concerns: the plan’s road-mile totals did not match local estimates (the county has approximately 800 miles of road, including about 300 miles of gravel and 500 miles of paved), the study covered only the east side of I-15, and available traffic counts and pavement-condition data need updates. Commissioners asked staff to use traffic-count equipment available from the Local Technical Assistance Center (LTAC) and to coordinate with the sheriff’s office for supplemental speed and flow data. One commissioner proposed adopting the resolution with an explicit statement that the plan covers the east side of I-15 only and that staff must continue work on a full countywide study.

Board action: The board adopted a resolution (Resolution 2025-20) adopting the Jefferson County transportation plan for the East Side of Interstate 15 with a recorded addition that staff continue progress toward an updated countywide traffic plan, arrange more traffic counts and clarify scope and mileage figures.

Next steps: Staff will pursue additional traffic counts, explore use of LTAC counters and sheriff’s data, and report back with a countywide traffic-plan timetable and cost estimate. The board noted that more comprehensive studies would help guide capital improvements and future requests for right-of-way acquisitions.