BY P.FURTH · PUBLISHED APRIL 26, 2012 · UPDATED DECEMBER 8, 2020 By: Laura Beth Solomon. Many people don’t understand the differences between a rotary and a modern day roundabout. If you try to google “rotary” or “roundabout” most sites say the terms are interchangeable. In Massachusetts, this confusion is extremely evident. Rotaries were the old way of designing circular…