Painted 'roundabout in a box' reduced speeds but raised bus and large-vehicle concerns, staff says

City staff reviewed the temporary "roundabout in a box" installed at Greenway Cross and Coho and presented early performance data on July 9. "Greenway Cross, to the west of the roundabout, decreased by 5 miles an hour," Ross said, citing the approach most affected by the treatment. Staff reported crash counts remained similar in the year before and after installation.

Staff and committee members said the primary shortcoming is that larger vehicles and buses cannot clear the center island and must cut across it; for that reason staff omitted splitter islands in the initial temporary installation. Ross described an iterative approach of temporary paint and rubber curbs followed by a permanent mountable center island and splitter islands at resurfacing time. "We would look at a mountable center island and mountable splitter islands; that would be similar to the roundabout just east of here at Bryant," Ross said, estimating a permanent mountable solution could cost roughly $50,000–$100,000.

Committee members applauded the cost-effectiveness and speed of the experimental approach, noting a measurable reduction in speeds and a likely reduction in stop‑sign running. One committee member said, "For the money we spent, this is having a great impact," while another raised concerns about nuisance effects and large‑vehicle maneuvers.

Next steps: staff will continue the iterative evaluation, finish the planned paint and marking work, and include the intersection in the Vision 0 safety plan so the consultant can evaluate permanent mountable infrastructure as part of longer-term resurfacing plans.