Roundabouts - that&#x27;s what I&#x27;m talking about.<p><a href="http:&#x2F;&#x2F;www.iihs.org&#x2F;iihs&#x2F;topics&#x2F;t&#x2F;roundabouts&#x2F;qanda" rel="nofollow">http:&#x2F;&#x2F;www.iihs.org&#x2F;iihs&#x2F;topics&#x2F;t&#x2F;roundabouts&#x2F;qanda</a> and others cite &quot;Retting, R.A.; Mandavilli, S.; Russell, E.R.; and McCartt, A.T. 2006. Roundabouts, traffic flow and public opinion. Traffic Engineering and Control 47(7):268-72&quot;. The above URL summarizes the paper as:<p>&gt; A study of three locations in New Hampshire, New York and Washington state where roundabouts replaced traffic signals or stop signs found an 89 percent average reduction in vehicle delays and a 56 percent average reduction in vehicle stops.<p>That URL then goes on to say:<p>&gt; Because roundabouts improve the efficiency of traffic flow, they also reduce vehicle emissions and fuel consumption. Installing roundabouts in place of traffic signals or stop signs has been found to reduce carbon monoxide emissions by 15-45 percent, nitrous oxide emissions by 21-44 percent, carbon dioxide emissions by 23-37 percent and hydrocarbon emissions by 0-42 percent. 6, 11, 12  Constructing roundabouts in place of traffic signals or stop signs reduced fuel consumption by an estimated 23-34 percent. 6, 11, 13<p>and<p>&gt; A 2005 Institute study documented missed opportunities to improve traffic flow and safety at 10 urban intersections suitable for roundabouts where either traffic signals were installed or major modifications were made to 10 intersections with signals. 14 It was estimated that the use of roundabouts instead of traffic signals at these intersections would have reduced vehicle delays by 62-74 percent.<p>Sounds to me like existing roundabouts at least competitive to state-of-the-art experimental smart traffic signals ... and have the advantage of working even when the power goes out, and don&#x27;t require more expertise in order to maintain.