> I've also seen fancy sensor-equipped traffic lights where the traffic flow was improved by a power outage turning the intersection into a (legal default) 4-wa

> I've also seen fancy sensor-equipped traffic lights where the traffic flow was improved by a power outage turning the intersection into a (legal default) 4-way stop. Major intersections. During rush hour. That fits one of the main points made in this article: traffic lights slow down traffic. Another one is that decreasing speed on intersections increases safety. The magic of roundabouts is that they accomplish the latter without needing the former.