For older drivers it seems roundabouts may be the optimal intersection design. Apparently for most age groups, surprisingly even for the impatient driver of any age.
Less accidents, more traffic flow. This from a University of Maine study which also found that, wait for it, a driver who travels straight through 10 similar roundabouts daily versus 10 signalized intersections would annually save 14 gallons of gas. If every licensed driver in the country did the same, the university says 2.7 billion gallons of gas would be saved annually.
The University of Maine study shows a decrease in accidents at a intersection that had a poor record, and that roundabouts can work even nears schools or retirement communities. There is other research that gives us similar results. The evidence builds.