Roundabout FAQs

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Learn the answers to common questions regarding roundabouts by clicking on the links below:


Roundabouts are a new concept, so why should we experiment with them?
Roundabouts are not a new concept. Much of the rest of the world has been utilizing roundabouts for decades. Back in the 1960s, Great Britain spent millions of dollars experimenting with the design of roundabouts to optimize their safety and capacity. Much of that experience, as well as the experience from Australia, Canada and mainland Europe, is being utilized to guide the design of roundabouts in the U.S. The first roundabout in the U.S. was built in 1990 in a suburb of Las Vegas, Nevada.

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What is the difference between a roundabout and a traffic circle/rotary?
Roundabouts are different from other types of circular intersections that you might have seen. They are not rotaries or the older traffic circles, which are still common in the northeastern United States, which typically have higher speeds on approaches and usually higher speeds within the circle. They may use stop- or signal-control, or they may require circulating traffic to yield to entering traffic. A roundabout is also not the same thing as a neighborhood traffic circle, typically used on local streets for speed control. 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.   

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How do roundabouts create better traffic flow?
Contrary to many peoples' perceptions, roundabouts actually move traffic through an intersection more quickly, and with less congestion on approaching roads. Roundabouts promote a continuous flow of traffic. Unlike intersections with traffic signals, drivers don’t have to wait for a green light at a roundabout to get through the intersection. Traffic is not required to stop – only yield – so the intersection can handle more traffic in the same amount of time.   

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How are roundabouts safer for motorists?
Roundabouts show an 86 percent decrease in fatal crashes, an 83 percent decrease in life-altering injury crashes, and a 42 percent overall decrease in the injury crash rate at intersections. Learn more from the Minnesota Department of Transportation

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Are roundabouts safe for pedestrians and bicyclists?
In general, pedestrians face far less risk at roundabouts than traditional intersections, primarily because of the slower speeds and the elimination of turns across the pedestrian crosswalks. Splitter islands both shorten the crossing distance for pedestrians and allow them to cross one direction of traffic at a time. All of this adds up to increased safety. Bicyclists can dismount and use the pedestrian crosswalk, or experienced bicyclists can ride through the roundabout.

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How do pedestrians cross a roundabout?
Pedestrians should stay in the designated crosswalks and never cross to the center island. The splitter islands can be used as a halfway point to check for approaching traffic. Click here to learn more about navigating a roundabout.

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How do bikes navigate a roundabout?
Bikes can either travel through the roundabout just like vehicles or they can be walked through crosswalks. Click here to learn more about navigating a roundabout.

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How is snow removed from a roundabout?
Many roundabouts exist across the country in snowy climates. Typically a snow plow truck will start on the inner most section of the circulating roadway, often on the truck apron, and keep circulating in a spiral outward with each revolution until the whole circle is cleared. Either the same plow vehicle or a second plow vehicle will clear the snow from the approaches and exits. Roundabouts are treated with anti-icing chemicals as necessary.

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How can large trucks and emergency vehicles make turns on a small roundabout?
Roundabouts are also designed with a truck apron, a raised section of concrete around the central island that gives large vehicles and vehicles with trailers more space to navigate the turn. The back wheels of the oversize vehicle can ride up on the truck apron so it may easily complete the turn, while the raised portion of concrete discourages use by smaller vehicles. Click here to learn more how large vehicles navigate roundabouts.

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Why are there so many tire marks on the concrete in the middle of the roundabout? Doesn’t this demonstrate that the roundabout isn’t working?
Roundabouts are also designed with a truck apron, a raised section of concrete around the central island that acts as an extra lane for large vehicles and vehicles with trailers. The back wheels of the oversize vehicle can ride up on the truck apron so it may easily complete the turn, while the raised portion of concrete discourages use by smaller vehicles. 

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What do I do when an emergency vehicle approaches while I am in the roundabout?
If an emergency vehicle approaches, exit the roundabout immediately and then stop. Do not stop in the roundabout. 

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