In 1903 the Columbus Circle opened in New York City, this was the first traffic circle to be built in the United States. Traffic Circles were constructed in New Hampshire from about the 1940’s to 1960’s. They fell out of favor beginning in the 1960’s because they relied on high speed merging of traffic and the traffic in the circle commonly yielded to traffic entering the circle causing traffic jams within the circle. While traffic circles fell out of use in the US many European countries modified the design and eventually created the modern roundabout. The modern roundabouts have since gained renewed interest in the US because of the safety benefits, high capacity, traffic calming effect, and aesthetic value they can bring to an intersection.

The information below is intended to answer some common questions and provide additional information to communities and the general public as to what roundabouts are and how they operate.

Also included are NHDOT roundabout design guidelines that supplement the FHWA Roundabout Guide.


Informational Posters

NHDOT Constructed Roundabouts

NHDOT Roundabout Listing

NHDOT Roundabout Pictures:

Design Information