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Ames City workshop previews Duff Avenue corridor plan; staff highlights safety gains and rail crossing study
Summary
At a July 21 workshop, staff presented a Duff Avenue Corridor study recommending long‑term multimodal upgrades — including a potential conversion from four lanes to a three‑lane cross section, an 8‑ft shared use path and upgraded pedestrian crossings — while also recommending a separate railroad‑crossing study to address frequent train delays.
Staff presented the Duff Avenue Corridor study to the Ames City Council on July 21, describing a long‑range plan that would prioritize safety, multimodal connections and traffic operations through 2050.
Kyle Thompson, transportation planner for the City of Ames, said the study area extends from the Union Pacific railroad crossing just south of Main Street north to 16th Street and builds on priorities from the regional MPO safety action plan and the city’s Walk, Bike, Roll plan. Thompson said two rounds of outreach produced 547 responses in March and 711 responses in June, with local property owners and downtown stakeholders included in both rounds.
John Witt, the project traffic engineer, summarized the technical analysis. He said existing average daily traffic ranges from about 12,600 vehicles per day near Lincoln Way/Main to roughly 9,000 north of 16th Street and that staff used a conservative 0.5% annual growth rate to forecast conditions. Witt said crash data for the corridor show 96 crashes over the past five years, about 24% of which were injury crashes, and that common crash types — rear‑end, sideswipe and left‑turn — are characteristic of an undivided four‑lane cross section.
“There’s an average of 38 trains per day on weekdays, and the average gate downtime is about 3 minutes 15 seconds,” Witt said, adding that video counts confirmed the data and that the crossing is effectively blocked for roughly two hours a day on average during normal operations.
Staff’s conceptual design emphasizes safety and multimodal access: an 8‑foot shared‑use path on the west side of the corridor, upgraded crossing treatments at East 12th Street near Mary Greeley Medical Center (including a refuge island and a pedestrian‑hybrid beacon that could also operate in an emergency‑vehicle mode), and a possible conversion of long four‑lane undivided segments to a three‑lane configuration (one travel lane each way plus a center two‑way left‑turn lane).
Thompson and Witt said the three‑lane conversion is commonly used on urban corridors with ADTs up to 15,000–20,000 and nationally has been associated with crash reductions in a broad range (staff cited a national range of roughly 19–47%, noting the actual local benefit would be context dependent). Modeling presented to council showed similar traffic operations between the existing four‑lane configuration and the proposed three‑lane section, with most intersections showing one to two seconds’ difference in delay under the study’s conservative assumptions.
Public feedback was mixed. Thompson told council that about 57% of respondents to the Round 2 survey were unsupportive or very unsupportive of the proposed changes while 43% were neutral or supportive; specific concerns in narrative comments included potential queuing from lane reductions during train events, Syride bus dwell times in travel lanes, winter maintenance responsibilities for a wider shared‑use path, and emergency‑vehicle access. Staff said Mary Greeley ambulance operations personnel had expressed conditional support for a three‑lane section in meetings with the project team.
On the 16th Street intersection, staff showed three alternatives: keep the existing all‑way stop, convert to a two‑way stop with enhanced pedestrian treatments, or construct a mini‑roundabout. Modeling showed the roundabout performs best for continuous flow and pedestrian refuges but would require right‑of‑way acquisition and a larger footprint; a two‑way stop could be implemented on an interim basis with lower construction impacts.
Staff emphasized that the corridor study is a long‑term visioning document and not an immediate construction plan. They recommended finalizing the study and returning to the council in the fall (September–October) with a final report and any recommendations for a separate detailed railroad‑crossing study. No formal council direction or vote was requested at the workshop.
Looking ahead, staff said design and implementation would likely proceed through phased capital programming and typical public‑input and final design processes; a separate, detailed railroad‑crossing investigation (including grade‑separation alternatives) would be required to fully evaluate solutions for the frequent train delays.
