Mapleton council directs staff to prepare plans both with and without West Maple Street extension after traffic modeling

Mapleton City Council reviewed travel‑demand modeling for the West Maple Street extension during a work session and directed staff to prepare two alternate Transportation Master Plan maps — one that removes the western connection to Highway 89/Double Day and one that retains it with proposed mitigation options.

Rob (staff) opened the session and turned the presentation over to Jeremy Surl of WCG, who described the model and its assumptions, including a 2050 planning horizon and socioeconomic inputs. Jeremy said the model projects roughly 8,000 daily trips crossing into Mapleton from the west if the Maple Street link is in place and about 4,000 vehicles per day at the key intersection where the road meets existing streets if the connection is built. He told the council that, as traffic engineers, the firm “always recommend[s] a grid” of connections to spread congestion rather than funnel traffic to a few corridors.

Why it matters: presenters and councilors said the connection would provide a direct west–east collector through the city that could improve emergency‑response routing and reduce pressure on neighborhood streets. Opponents and some neighbors have raised concerns about property impacts, conservation easements on private parcels, and the scale of construction required.

Council discussion focused on several tradeoffs. Staff and the presenter noted that UDOT spacing standards for signals (about a half mile between signals on Highway 89) make a new signal at Sunrise Ranch or a nearby crossing uncertain; presenters said exceptions are possible but would require coordination or political effort with UDOT. Staff also flagged conservation easement constraints and wetlands on portions of the corridor and said the city holds an easement that imposes stipulations on road improvements for property owners, which would add steps to any project.

Modeling and alternatives: council members and staff reviewed scenarios where the western extension is not built. In that scenario traffic redistributes to Slant Road, Sunrise Ranch Drive and Evergreen Road, producing failing conditions in some intersections and increasing the likelihood the city would need to fund intersection improvements (roundabouts, signals or turn lanes) on those corridors. Staff estimated Slant Road could reach roughly 11,000 average daily trips at the south end with the connection in place and could be higher if the connection is not built; Sunrise Ranch buildout was cited in discussion as producing about 4,200 daily trips independently.

Next steps and cost: council asked staff to return with detailed turning‑movement data, a rough cost estimate for the western connection (presenters cited prior planning estimates in the range of about $7–8 million as an order‑of‑magnitude figure), and costs for mitigation options such as roundabouts and intersection widening. Rob summarized the council’s direction: prepare a revised Transportation Master Plan that omits the Highway‑89 to Double Day extension and, in parallel, retain the previously shown plan so the council can compare both options with accompanying mitigation and cost analysis.

Procedure and timeline: staff said a full set of materials will be returned for council consideration in April (the earlier target of the 18th was described as too fast for complete analysis). The work session closed by motion and the council moved into its regular meeting.

The council’s decision to ask for two plan alternatives preserves the ability to weigh long‑term regional commitments and local property impacts against traffic operations and safety improvements; staff will return with the comparative technical and budget information required for a final decision.