Roundabouts

Roundabouts are a type of circular intersection defined by the basic operational principle of entering traffic yielding to vehicles on the circulatory roadway. Roundabouts have geometric features providing a reduced speed environment that offers substantial safety advantages and excellent operational performance.

How to Navigate a Roundabout

When approaching a roundabout, slow down and observe advisory speed limit signs. Stop for pedestrians. IT’S THE LAW.

When entering a roundabout, yield to traffic already in the circle. Look left and then enter when there is a safe distance in the circulating traffic.

When at the roundabout, drive counter-clockwise and obey signs at all times.

When inside the roundabout, DO NOT STOP. You have the right of way.

Roundabout Guidance Manual

Guidelines covering roundabouts (Georgia DOT Design Policy Manual: Chapter 8).

View Manual

Analysis Tool
Background
FAQs
Training

Roundabout Analysis Tool 4.2

The Georgia DOT Roundabout Analysis Tool is to be used for preliminary design and planning purposes only. As an analysis tool, it provides useful measures such as capacity, queue, and delay by which its operational ability can be assessed. As a design tool, it allows the designer to quickly gauge initial geometric constraints (single lane, multilane, bypass lanes, etc.), that could not be known without some level of traffic analysis. The Roundabout Analysis Tool is most useful when determining the feasibility of a roundabout at an intersection and should accompany any preliminary study. In addition to this tool, there are many software packages available for use, namely RODEL and SIDRA.

Download Analysis Tool

Software Packages
SIDRA
RODEL
VISSIM
Highway Capacity (HCS)
ARCADY

Roundabouts have demonstrated substantial safety and operational benefits compared to other forms of intersection control, with reductions in fatal and injury crashes of 60-87 percent. The benefits apply to roundabouts in urban and rural areas and freeway interchange ramp terminals under a wide range of traffic conditions. Although the safety of all-way stop control is comparable to roundabouts, roundabouts provide much greater capacity and operational benefits. Roundabouts can be an effective tool for managing speed and transitioning traffic form a high speed to a low speed environment. Proper site selection and channelization for motorist, bicyclists, and pedestrians are essential to making roundabouts accessible to all users. In particular, it is important to ensure safe accommodation of bicyclists at higher speed roundabouts and for pedestrians with visual or cognitive impairments.

Introduction to Roundabouts: Roundabout Planning, Design and Operational Analysis

Course Description
In this course, you will review the planning phase of a roundabout, the operational analysis steps, and detailed design guidelines for roundabouts. The planning phase focuses on where roundabouts should be considered and issues inherent in the design and operation. The operational analysis covers the detailed performance of a roundabout and typical measures of effectiveness, such as capacity, delay, and queues. The design phase includes issues related to size, horizontal and vertical alignment, transit, pedestrians, bicyclists, signing, and striping. In addition, you will perform exercises individually and in team settings and apply and discuss the various elements, standards, and features relevant to the development and design of modern roundabouts.

The basis for the course is the FHWA document, Roundabouts: An Informational Guide, supplements to the FHWA guide prepared for the Kansas DOT and other states, and ongoing instructor involvement in NCHRP research and TRB, ITE, NCUTCD, and IESNA Committees.

Course Topics

Characteristics of early circular intersections and present-day roundabouts
Roundabout site selection and planning
Effectiveness measures for roundabouts
Roundabout design

If you're interested in attending this course please submit an email with your name and contact information (email and phone) to roundabouts@dot.ga.gov

STATEWIDE ROUNDABOUTS MAP

Please access the map below to view roundabout locations in Georgia. Use the map control tools to navigate and zoom.

CONTACTS

Please contact the following if you experience problems accessing the Analysis Tool or have questions regarding Roundabouts:

Georgia DOT Roundabouts Team
Office of Traffic Operations
roundabouts@dot.ga.gov

Roundabout Facts

Roundabouts can be a safer and more efficient alternative to traditional intersections, which are one of the most common sites of crashes.
Roundabouts require reduced speeds, giving drivers more time to react to other vehicles and pedestrians.
Roundabouts can save money. There is no traffic signal equipment to install, repair or maintain.
Roundabouts can reduce congestion. When operating inside a roundabout, a driver typically experiences a lower delay time than at intersections with traffic lights or stop signs.
Roundabouts significantly reduce pollution, noise impacts and fuel consumption.

View Factsheet

Safety

Roundabouts can reduce crashes that may result in serious injuries or fatalities by 78 to 82 percent compared to conventional intersections controlled by traffic lights or stop signs.