Roundabouts in Roswell

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Professional Shot 4_thumb The roundabout at Grimes Bridge Road and Norcross Street/Warsaw Road by all accounts, seems to be a huge improvement over the unsafe, accident-prone signalized intersection. Despite the lack of accidents, two distinct issues have emerged, both of which are related to driver behavior: the failure to yield upon entering the roundabout and the failure to stop for pedestrians while entering or exiting the roundabout.

Roswell DOT could post study after study that statistically prove roundabouts are safer than standard intersection controls (i.e. turn lanes with signals or two-way stop control) but what it really comes down to is the general lack of civility on our roadways.  At times, there are too many people in a hurry who are not willing to yield to others.

So, for the sake of you, your neighbors, and others, slow down, yield to those in the roundabout, look for and if necessary, stop for pedestrians!

Which intersection type moves more traffic?  Four-Way Stop Controlled or a Roundabout?

Watch this segment of TLC's Mythbusters where the hosts test the myth that Four-Way Stop Controlled intersections are more efficient.  (Opens YouTube in a new window.)

Did Roswell build DuPont Circle?

The picture to the right is an aerial shot of DuPont Circle in Washington D.C. At the top of this page is an aerial shot of the roundabout at Grimes Bridge Road and Norcross Street/Warsaw Road. Do they look similar to you?

DuPont Circle is a loud, congested area with cars coming from six different directions following signals timed to speed people through the intersection. The Grimes Bridge/Norcross/Warsaw roundabout is slower, quieter, and has far less of an impact.

The table below was taken from the Wisconsin DOT website and describes the major differences between modern roundabouts and the old traffic circles located primarily in the northeast United States.

Major Differences between Modern Roundabouts and Traffic Circles


Modern Roundabout

Traffic Circle or Rotary

Control at Entry

Drivers yield to circulating vehicles

Priority given to entering vehicle

Operational Characteristics

Vehicles sorted by destination approach; weaving is minimized

Weaving is unavoidable; weaving sections provided for conflicting movements


Large entry angle slows entry speed

Small entry angle allows faster entry speed


Relatively lower speeds (<25 mph)

Higher speeds are observed (>25 mph)

Circle Diameter

Smaller; improved safety

Larger; decreased safety

Pedestrian Crossing

No pedestrian activity allowed in the center island

Some larger circles allow pedestrians to cross into the center island

Splitter Islands

Required (acts as pedestrian refuge)



There is no parking allowed within the circle or within close proximity of the yield bar

On larger traffic circles, some parking may be available on the circulating roadway

Roundabouts and Older Drivers (from the Insurance Institute for Highway Safety)

Roundabouts eliminate many of the driving scenarios that can be challenging for older drivers. Relative to other age groups, senior drivers are over-involved in crashes occurring at intersections. In 2008, 37 percent of drivers 70 and older in fatal crashes were involved in multiple-vehicle intersection crashes, compared with 22 percent among drivers younger than 70.

Older drivers' intersection crashes often are due to their failure to yield the right-of-way. Particular problems for older drivers at traditional intersections include left turns and entering busy thoroughfares from cross streets. Roundabouts eliminate these situations entirely. A 2007 study in six communities where roundabouts replaced traditional intersections found that about two-thirds of drivers 65 and older supported the roundabouts.

Although safety effects of roundabouts specifically for older drivers are unknown, a 2001 IIHS study of 23 intersections converted from traffic signals or stop signs to roundabouts reported the average age of crash-involved drivers did not increase following the installation of roundabouts, suggesting roundabouts may not pose a problem for older drivers.

Roundabout and Pedestrians

Just as drivers will adjust to the new traffic pattern after a roundabout is opened, so too will pedestrians need to educate themselves on crossing the road where there is no signal present. At a standard signalized intersection, pedestrians are lured into a false sense of security by the appearance of a WALK symbol. In fact, most transportation experts agree more pedestrians are struck and injured (or killed) by vehicles turning into the crosswalk on a GREEN/WALK condition.

The installation of the splitter island in the middle of the road actually serves two purposes: it forces cars to turn in the correct direction while entering the roundabout, but it also acts a refuge for pedestrians while waiting for gaps to appear in the traffic. As much as it is the responsibility of the driver to watch for pedestrians, it is equally important the pedestrians wait for an appropriate gap in traffic before beginning or concluding their crossing.

Watch a clever animated video from Hawaii about how to use a roundabout.

Additional Resources

Georgia DOT Roundabouts webpage

American City & County Roundabout Article

Federal Highway Administration (US DOT) Roundabouts website

Insurance Institute for Highway Safety Q&A

Kittelson & Associates Roundabouts database - contains a searchable database of roundabouts in the U.S.