An overhead view of Common Street, including the new roundabout on the right end, and the new traffic light at Common and Spring streets (left side, near the green sections). A much used road in Watertown has undergone a transformation this summer, and drivers will see a new roundabout and a traffic light. The roundabout is located at the five-prong intersection of Common Street with Orchard Street and Church Street. Workers have completed the repaving of the intersection and the roundabout is operational, according to the Watertown Department of Public Works. “The contractor has placed temporary pavement markings, signage and message boards throughout the area,” the DPW announcement said.