For traffic planners, roundabouts have been huge game changers. Decades of studies show that the introduction of traffic circles greatly improves flow and reduces collisions overall by slowing vehicles down. Another plus is the reduction in greenhouse gases, from fewer idling cars, and increased safety for pedestrians, who have shorter distances to travel. They’re cheaper to maintain than traffic lights and work even during prolonged power outages, such as the kind we experienced recently during Post-Tropical Storm Fiona.