Roundabouts
This set of roundabout visualisations shows the ratio of roundabouts in the U.S. compared with countries like France, where motorists are 25 times more likely to encounter a roundabout than in America. American roundabouts are also not spread evenly throughout the land, but amass in certain places like Florida (1,283 roundabouts), but virtually disappear in other areas like Wyoming/South Dakota/North Dakota (not even 50 among the three states).
This project was prepared for City Lab in 2016.