Chapter 7 - At Grade Intersections

7.6. Roundabouts

A modern roundabout is a type of circulatory roadway in which all traffic flows counterclockwise around a central island. GDOT recognizes that the modern roundabout is a viable intersection alternative when placed in the appropriate location, and designed properly for the local conditions. In recognizing this, the GDOT Division of Preconstruction and Division of Operations have developed guidance for the use of modern roundabouts in Georgia. This directive is for the purpose of facilitating the standardization of modern roundabouts on state facilities. It is not meant to be a design guide.

For more information regarding modern roundabout design, refer to the FHWA publication, Roundabouts: An Informational Guide RD-00-67 (2000). Furthermore, in the absence of specific Georgia design guidelines, FHWA guidelines should be used.

GDOT will only accept requests for roundabouts at locations that have single-lane approaches. The roadways involved should have total entry Average Daily Traffic (ADT) no higher than 16,000, with an entering and circulating flow no higher than 1,800 vph. The intersections should have somewhat equal entry flow, with a maximum 75/25 split of mainline traffic to side-street traffic.

At this time, only single-lane modern roundabout designs are allowed on Georgia's state routes.