Roundabouts save lives

Studies have shown that roundabouts are safer than traditional stop sign or signal-controlled intersections.

Most significantly, roundabouts REDUCE the types of crashes where people are seriously hurt or killed by 78-82% when compared to conventional stop-controlled and signalized intersections, per the AASHTO Highway Safety Manual.  The FHWA Office of Safety identified roundabouts as a Proven Safety Countermeasure because of their ability to substantially reduce the types of crashes that result in injury or loss of life. Roundabouts are designed to improve safety for all users, including pedestrians and bicycles. Source

Specifically, other statistics from the Federal Highway Administration (FHWA) state that roundabouts save lives by reducing fatalities by up to 90%. Source

Roundabouts eradicate the risk of drivers running stop signs and red lights. Source

Roundabouts create up to 75% fewer conflict points than a four-way intersection. Conflict points are any point where the paths of two through or turning vehicles diverge, merge or cross. Source

Roundabout vs. Four-Way Intersection Conflict Points

Roundabouts promote safety in several ways. At traditional intersections with stop signs or traffic signals, some of the most common types of crashes are right-angle, left-turn, and head-on collisions. These types of collisions can be severe because vehicles may be traveling through the intersection at high speeds. With roundabouts, these types of potentially serious crashes essentially are eliminated because vehicles travel in the same direction and at low speeds – generally less than 20 mph in urban areas and less than 30-35 mph in rural areas. Source

Now, to some other information about Roundabouts…

Would you prefer to slow down and wait for your turn to enter an intersection or sit at a red light.  How many times do you pull up at a red light and nobody is there but you?

Roundabouts have several distinguishing characteristics and benefits, setting them apart from other intersection types.  Traffic can move freely through roundabouts.  This makes them more efficient than signalized or stop-controlled intersections.  Unlike other types of intersections, roundabouts are designed to slow the speed of vehicles entering by deflecting them from a straight-line path into the roundabout.  Drivers approaching the roundabout have time to judge for gaps in the circulating traffic and either yield or adjust their speed before entering the intersection.  This allows for safer entries into circulating traffic. Source

What about trucks and other large vehicles? Are they able to navigate through roundabouts?

Roundabouts can be built to accommodate the turning radii of large trucks and trailers just like any other intersection. Roundabouts generally have truck aprons – a slightly raised area around the inner circle that provides trucks, buses, and other large vehicles additional room to navigate the roundabout.

Roundabouts can work very well on a wide range of road types, including freeway interchanges, urban and suburban corridors, and high-speed rural roadways.  Some people think they can’t be constructed on State roads, but that’s just not true.  There are numerous examples of successful roundabouts built on State roads, and the number is growing rapidly. Source

Roundabouts are designed to accommodate vehicles with a large turning radius such as buses, fire trucks and eighteen wheelers. Roundabouts provide an area between the circulatory roadway and the central island, known as truck apron, over which the rear wheels of these vehicles can safely track. Source

Roundabouts are much more than a street device. Roundabouts have the potential to transform an area.  Not only is a roundabout a radical improvement to a roadway, but roundabouts can be used as a visual enhancement to an area as a gateway.  Roundabouts are a tool that increases safety along the street, enhances driver attentiveness, reduces automobile idling, and efficiently streams traffic through an area.  Roundabouts are cost effective and safe thousands of dollars that traditional intersections require for the electricity of signals.  Even though many people are skeptical about roundabouts—thinking they are confusing, overwhelming, and hinder traffic flow—studies have proved the opposite.  The more roundabouts that are implemented and effective, the more drivers will be accepting.  It is only a matter of time that roundabout implementation in the United States will match the Europeans. Source

“Well-designed roundabout intersections have been proven to not only help traffic move more efficiently but also reduce the risk of fatal and serious crashes.  This is why the Federal Highway Administration is strongly encouraging State and local leaders to take a hard look at roundabouts as an alternative to conventional intersection designs.  If you’re looking for ways to reduce congestion, improve safety, and enhance your community’s environment; modern roundabouts may be just the solution for you.” Source

Ultimately, most people will find out that roundabouts really work well.  Support always goes up after people get used to them.

Back to Roundabout Safety…

Did you know that more than 20 people are killed and many more are seriously injured in crashes at intersections every day in the United States?  Did you know that most of these deaths and injuries are due to right-angle crashes that occur at signalized and stop-controlled intersections?  How much time do you spend stopped at a red light waiting for the light to change when there is no traffic on the cross-street?  Did you know there is an intersection alternative that is substantially safer than signalized and stop-controlled intersections and much more efficient. Source

The USDOT’s Federal Highway Administration (FHWA) has identified modern roundabout intersections as one of nine proven life-saving roadway safety strategies. Source

The U.S. Department of Transportation’s Federal Highway Administration reports that roundabouts reduce fatal and serious crashes by up to 82% nationally, compared to conventional stop-controlled and signalized intersections. The FHA cites this highway safety manualfor that information. Source

Roundabouts Save Lives…



U.S. Department of Transportation – Federal Highway Administration

Washington State Department of Transportation

National Cooperative Highway Research Program – Roundabouts: An Informational Guide

Insurance Institute for Highway Safety – About Roundabouts

U.S. Department of Transportation – Federal Highway Administration

Louisiana Department of Transportation and Development

Iowa State University

University of Cincinnati

NCDOT Roundabout Evaluation



What is a roundabout?

Roundabouts are one-way, circular intersections designed to improve safety and efficiency for motorists, bicyclists and pedestrians.

In a roundabout, traffic flows through a center island counterclockwise.

A roundabout redirects some of the conflicting traffic, such as left turns, which cause crashes at traditional intersections. This is because drivers enter and exit the roundabout through a series of right-hand turns.

What are the advantages of roundabouts? 

A well-designed roundabout can improve safety, operations and aesthetics of an intersection.

Greater safety is achieved primarily by slower speeds and the elimination of more severe crashes and operation is improved by smooth-flowing traffic with less stop-and-go than a signalized intersection.

Aesthetics are enhanced by the opportunity for more landscaping and less pavement.

What do statistics from the Federal Highway Administration (FHWA) say about roundabouts?

Roundabouts save lives by reducing fatalities by up to 90%

Reducing injury crashes up to 76%

Reducing pedestrian crashes up to 30% to 40%

Creating up to 75% fewer conflict points than a four-way intersection. Conflict points are any point where the paths of two through or turning vehicles diverge, merge or cross

Roundabouts save money by:

Reducing road electricity and maintenance costs by an average of $5,000 per year

Eliminating the costs to install and repair signal equipment

Providing a 25-year service life when compared to the ten-year service life of signal equipment

Roundabouts provide environmental benefits by:

Reducing vehicle delay and the number and duration of stops compared with signalized intersections thus decreasing fuel consumption and carbon emissions. Fewer stops and hard accelerations mean less time idling.

How are modern roundabouts different than traffic circles and rotaries?

Modern roundabouts are significantly different than older style traffic circles and rotaries in how they operate and are designed:

Rotaries and traffic circles may have two-directional flow and are typically much larger than the modern roundabout.

The compactness of a modern roundabout helps keep speeds low and makes it easier for drivers to stay oriented and judge the speed of the vehicles before entering the roundabout.

Modern roundabouts require entering traffic to yield not merge at all entries. Whereas traffic circles and rotaries may require circulating traffic to yield to entering traffic.

What are the general principles of using a roundabout?

Think of roundabouts as a series of “T” intersections, where entering vehicles yield to one-way traffic coming from the left. A driver approaching a roundabout must slow down, stop or yield to traffic already in the roundabout, and yield to pedestrians in the crosswalk.

Then, it’s a simple matter of making a right-hand turn onto a one-way street.

Once in the roundabout, the driver proceeds around the central island, then takes the necessary right-hand turn to exit.

Can roundabouts accommodate larger vehicles?

Yes. Roundabouts are designed to accommodate vehicles with a large turning radius such as buses, fire trucks and eighteen wheelers. Roundabouts provide an area between the circulatory roadway and the central island, known as truck apron, over which the rear wheels of these vehicles can safely track.


Again, Roundabouts Save Lives…