Updated July 29 Portland’s first traffic roundabout set to open Friday The Deering's Corner Roundabout reorganizes traffic flow in what had been a six-way intersection at the intersections of Deering and Brighton avenues and Falmouth Street. This bird's-eye photo of the roundabout, taken June 8, was posted on Portland's website. Portland will open the Deering’s Corner Roundabout, the first to be built in the city, to traffic on Friday. The roundabout, at the intersections of Deering and Brighton avenues and Falmouth Street near the University of Maine School of Law and University of Southern Maine, marks a significant change in how the city will handle the heavy traffic that passes through the neighborhood.