Roundabouts are Here to Stay — Here’s Why You’ll Agree

Scott Zehngraff, PE, PTOE , Georgia Traffic Practice Lead, Barge Design Solutions

Roundabouts are gaining ground fast, and it’s not by chance. Safety is leading the charge.

Across the United States, agencies are recognizing that roundabouts are not just an alternative to traditional intersections. They are a proven solution, backed by data. The Insurance Institute for Highway Safety, supported by Federal Highway Administration research, reports that roundabouts result in a 90% reduction in fatal crashes, a 75% reduction in injury crashes, and roughly a 40% reduction in total crashes compared to traditional signalized intersections.

States like Georgia have shown how quickly that shift can happen. What started as just a few installations for the state in the early 2000s has grown into more than 200 roundabouts on its state routes today. That momentum didn’t happen overnight. It reflects active leadership, a willingness to learn from early adopters, and a clear understanding that investing in safer intersections saves lives.

Policy is also playing a key role. With frameworks like Intersection Control Evaluation (ICE) to guide decisions, safety is no longer optional in intersection design. It is required. When roundabouts are considered alongside other options, their ability to reduce the frequency and severity of crashes often makes the decision easy.

Changing Public Perception of Roundabout Design

Roundabouts didn’t win people over easily. Early reactions were cautious and often resistant. Drivers were unsure how to navigate roundabouts and preferred the familiarity of traffic signals. That hesitation placed a real need for education. Agencies had to show how roundabouts work and why they outperform traditional signals and all-way stop control in many cases.

New roundabouts were also closely monitored. The Georgia Department of Transportation continues to conduct In-Service Reviews (ISRs) on select roundabouts after they open, evaluating traffic operations and crash data to identify opportunities for improvement.

What changed next was simple. User experience. Once a roundabout opened, drivers adapted quickly. What felt unfamiliar became intuitive. Confidence replaced doubt. As nearby communities saw them in action, trust spread just as fast as the design itself.

Today, success is easy to spot. Traffic moves without delay. Drivers move through with clarity, guided by clear signage and pavement markings. The best results come from the right locations, where safety or congestion was already a concern. Over time, the data backs up the decision to install roundabouts. Fewer crashes, better flow, and a public that no longer questions the design but expects it.

Shifting the Mindset from Straight and Fast to Curved and Safe

For decades, roadway intersection design focused on straightening paths and maximizing speed. Roundabouts turn that thinking on its head. Curvature is not a constraint. It is the solution for improved safety and flow.

When stopped at a signal, which is often on a straight section of roadway, drivers watch for a green light and then move without hesitation. This can happen without the driver realizing another car is running a red light at a high speed—a dangerous scenario. This is where a roundabout’s curvature can change the outcome. Every driver has to slow down, look left, and decide whether it’s safe to proceed. That moment of awareness can make a life-saving difference.

Reducing Crash Severity Through Strategic Roundabout Design

The curvature of a roundabout naturally slows vehicles, reducing speeds to around 20 to 25 mph. Compare that to a signalized intersection where vehicles may move through at 55 mph or more. The result is a sharp drop in crash severity, especially in rural areas.

When adding chicanes—reverse curvature—on the high-speed approaches to roundabouts, speeds are further reduced before a vehicle ever reaches the roundabout. This works particularly well in rural areas, where speeds are a real concern. In moderate-speed settings, subtle approach curvature can achieve similar results. The outcome is consistent. Slower entries. Fewer high-impact collisions. And intersections that are built to prevent the worst-case scenario

Providing Design Flexibility for a More Tailored Traffic Solution

Roundabouts give designers room to think beyond a standard solution. Location, size, and layout can all be shaped to fit the site, not forced onto it. That flexibility makes it easier to work through constraints and still deliver a solution that performs.

Over time, that adaptability turns into real value. Roundabouts reduce the need for ongoing maintenance, improve operations, and most importantly, continue to deliver safety benefits year after year. Other options, such as reduced-conflict U-turns, can improve safety in certain conditions but are limited to divided roadways. Roundabouts work in more places, solving more problems for the long term.

Designing Turbo Roundabouts for Growing Traffic Volumes

Roundabouts continue to gain momentum as safety data drives design decisions forward. At the same time, traffic volumes are increasing, which can challenge the effectiveness of single-lane roundabouts and often requires multi-lane solutions.

That’s where turbo roundabouts come in.

A key limitation of traditional multi-lane designs is lane discipline—drivers can drift or switch paths within the circle, especially when striping is overlooked or misread. Turbo roundabouts address this directly with raised lane dividers that guide vehicles through a fixed path.

This design removes ambiguity, keeps traffic properly aligned, and naturally slows speeds through the intersection. The result is a more controlled flow with fewer conflict points and a lower risk of sideswipe crashes.

Georgia is already leading the way in implementing these designs, and other states are expected to follow as the safety benefits continue to prove themselves.

Creating Curb Appeal for Greater Community Impact

Roundabouts can be a strong visual asset in a community. Landscaping and thoughtful design replace the clutter of overhead wires and signal heads. The result feels intentional and can fit the community’s character, improving connections for the people who live and work there. The driving experience improves, too. Traffic keeps moving. Speeds are lower. Drivers stay more aware of each other, rather than waiting at a light while others rush through.

The case for roundabouts comes back to one thought. Roundabouts save lives and reduce injuries. Added benefits strengthen the case, including improved aesthetics, lower maintenance needs, and reduced emissions. It is a solution that delivers on multiple levels for both drivers and communities.  

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About the Author

Scott Zehngraff, PE, PTOE, is a consultant with Barge Design Solutions, where he serves as the Georgia Traffic Practice Lead in Transportation Services. In his role, he continues to support the Georgia Department of Transportation (GDOT) in advancing roundabouts and other safety-focused projects. Scott retired from GDOT in December 2022 after a 28-year career, championing the implementation of roundabouts across the state. His work included developing the first GDOT roundabout policies, guiding early projects, advancing Intersection Control Evaluation (ICE), and authoring the GDOT Roundabout Design Guide. 

Scott has delivered several national presentations on roundabouts for TRB and ITE. He also serves as chair of the Roundabout Joint Task Force for NCUTCD and chairs the Georgia ITE Roundabout and Alternative Intersection Committee.