City recommends reverting to signalized intersection for Liberty Pike–Mallory Lane after roundabout analysis
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Summary
City staff recommended reverting to a signalized intersection for Liberty Pike and Mallory Lane after consultants concluded a roundabout could not be sized within the site limits without major impacts.
City staff recommended on Oct. 20 that the planned improvement at Liberty Pike and Mallory Lane move from a proposed roundabout to an enhanced signalized intersection after a new traffic analysis indicated capacity and geometry constraints.
The project, funded in the city’s CIP, began with designs for a signalized intersection and later shifted to a roundabout concept at the board’s request. Staff said the consultant exhibits for a roundabout required a diameter larger than the available footprint and would have encroached on adjacent properties including a CVS and a nearby apartment complex.
Jonathan [last name not provided], the project lead, and consultant RK&K reported that the smaller roundabout configuration produced failing volume-to-capacity ratios in the 5- to 10-year horizon. "When that volume-to-capacity gets over... it starts to fail exponentially," staff said, explaining why they recommend returning to a signal plan that can be tuned with signal timing.
Board reaction was mixed. Alderman Oliver Burger urged additional review and asked staff to convene a focused Zoom session with consultants and engineering experts before the board finalizes scope, citing alternative geometric roundabout designs (for example, peanut-shaped layouts or metered two-leg designs) used in other cities. "I just wanna come in in the next week, and I wanna have a Zoom call with these gentlemen so I can feel... that I'm okay with this," Burger said.
Several aldermen stressed pedestrian safety and neighborhood character. Alderman Bev Brown said she would oppose abandoning the roundabout because of long-term pedestrian safety and streetscape benefits; Alderman Matt Baggett and others emphasized operational reliability and noted the McEwen roundabout example where smaller roundabouts have experienced queueing problems.
Staff said reverting to a signalized design will allow left- and right-turn lane optimization and is more likely to meet projected traffic demands without taking significant private property. The project remains in the CIP; staff said they will update the design, revisit right-of-way needs and present refined cost and schedule estimates.
Ending: Staff agreed to arrange additional technical discussions with board members and outside engineers and to return to the board with updated plans and cost estimates before advancing right-of-way acquisition or construction.
