Designers plan two‑lane roundabouts, mountable medians and truck accommodations

The presenter reviewed technical roundabout geometry planned for the US 127 corridor, saying the northern portion will use two‑lane roundabouts where appropriate and describing mountable median treatments to accommodate large vehicles. He noted a double roundabout diameter of about 165 feet and that two 16‑foot travel lanes would be typical in the larger two‑lane circles.

To ensure truck access the design includes a roughly 15‑foot mountable stamped concrete band (about 2 inches high, curved) to allow the trailer to ride up when needed; the presenter referenced a design vehicle AWB67 used in vehicle tracking checks. “Their front wheels will be in the lane. They'll all track into the orange like that is designed,” the presenter said while describing semi off‑tracking.