Automotive
Carmel has become internationally known for its roundabout network. They even hosted the 2011 Rundabout Conference.
Since the late 1990’s Carmel has been building and replacing signalized intersections with roundabouts. Carmel now has 100 roundabouts, more than any other city in the United States.
Carmel builds roundabouts because of their safety record, their compatibility with the environments, their aesthetics and their ability to make it easier for pedestrians and bicyclists to navigate. In Carmel, where roundabouts have replaced signals or stop signs at intersections, the number of injury accidents has been reduced by about 80 percent and the number of accidents overall by about 40 percent. Our numbers are similar to those reported by the Insurance Institute for Highway Safety.
Roundabouts work by reducing speed and, therefore, crash severity. Vehicles are forced to slow down to between 15 and 35 mph as they negotiate the curve of the roundabout.
Meanwhile, the most common (and severe) types of crashes at a conventional intersection — right-angle, left-turn and head-on collisions — are virtually eliminated as cars are all traveling in the same direction within the roundabout.
Also the incentive to speed up to catch the yellow light, or the need to slam on the brakes at a red, helps reduce rear-end collisions. As all traffic goes the same way, collisions with pedestrians also are less frequent, with some studies showing a 75 percent reduction.
http://www.carmel.in.gov/index.aspx?page=123
http://www.iihs.org/iihs/topics/t/roundabouts/qanda#roundabouts
https://www.cars.com/articles/circular-logic-making-intersections-safer-in-a-roundabout-way-1420692633893/
