Roundabouts Save Fuel

Some research in the USA that examined intersections that switched from stoplights to a roundabout proves that roundabouts are greener.

Intersections with roundabouts generated between 55% and 61% less carbon dioxide, depending on the time of day. Emissions of hydrocarbons, also greenhouse gases, dropped by between 62% and 68%. His paper, which is admittedly a bit of tough read, is here.