Roundabouts

A Safer Choice

U.S. Department of Transportation

Federal Highway Administration

U.S. Department of Transportation

Federal Highway Administration

Education is key.

Education is vital to the acceptance and success of a roundabout. 

Navigating a roundabout is easy. But because people can be 

apprehensive about new things, it’s important to educate the public 

about roundabout use. 

There are just a few simple guidelines to remember when driving 

through a roundabout:

1. Slow down.

2. If there’s more than one lane, use the left lane to turn left, 

the right lane to turn right, and all lanes to go through, 

unless directed otherwise by signs and pavement markings.

3. Yield to pedestrians and bicyclists.

4. Yield at the entry to circulating traffic.

5. Stay in your lane within the roundabout and use your rightturn signal to indicate your intention to exit.

6. Always assume trucks need all available space — 

don’t pass them!

7. Clear the roundabout to allow emergency vehicles to pass.

Design standards for roundabouts continue to evolve, and not all features of existing 

roundabouts meet current recommended practice. Please refer to FHWA’s web site 

for recommendations on current design practice.

Original source photo by Lee Rodegerdts. Photo has been altered to illustrate

 roundabout and updated signage.

“Personally, I love them, and I’ll tell you 

why. You only have to stop one lane of 

traffic, then go to the middle and wait. 

The cars can’t go much faster than 20 mph 

through the roundabout so the crossing 

aspect is great.” 

Denise Haltom

School Crossing Guard, Suamico, Wisconsin

Green Bay Press-Gazette

February 6, 2001

“We have had a lot of people not very 

happy about the idea of roundabouts, but 

after they are constructed, those fears 

mostly go away.”

Brian Walsh

Washington State Department of Transportation

Seattle Times

June 5, 2002

“We all know people speed up to get 

through a yellow light. But at the 

roundabout, all the vehicles have to slow 

down ... we have almost 50 roundabouts 

now, we have a lot [fewer] personal 

injuries. We have fewer fatalities.”

James Brainard

Mayor, City of Carmel, Indiana

www.nbc17.com 

November 8, 2007

Visit safety.fhwa.dot.gov to learn 

more about roundabouts

09-0876

FHWA-SA-08-006
What is a roundabout?

A roundabout is a type of circular intersection 

with yield control of entering traffic, islands on the 

approaches, and appropriate roadway curvature to 

reduce vehicle speeds. 

Modern roundabouts are different from rotaries and 

other traffic circles. For example, roundabouts are 

typically smaller than the large, high-speed rotaries 

still in use in some parts of the country. In addition, 

roundabouts are typically larger than neighborhood 

traffic circles used to calm traffic.

A roundabout has these characteristics:

Why consider a roundabout?

Compared to other types of intersections, roundabouts 

have demonstrated safety and other benefits. 

Roundabouts:

> Improve safety

•	 More than 90% reduction in fatalities*

•	 76% reduction in injuries**

•	 35% reduction in all crashes**

•	 Slower speeds are generally safer for pedestrians

Source: Roundabouts: An Informational Guide. Federal Highway Administration, 

Washington, D.C., latest version, except as noted.

Walk around the 

outside; don’t 

cross through 

the middle

Ride your bike 

as a vehicle or 

walk your bike 

as a pedestrian

Tips for safely walking and biking 

through a roundabout

No need to 

change lanes 

to exit

Can have 

more than 

one lane

Yield signs 

at entries

Geometry 

that forces 

slow speeds

Counterclockwise 

circulation

Generally 

Circular Shape

[ Traditional intersection ] [ Roundabout ]

* “Safety Effect of Roundabout Conversions in the United States: Empirical Bayes

Observational Before-After Study.” Transportation Research Record 1751, Transportation 

Research Board (TRB), National Academy of Sciences (NAS), Washington, D.C., 2001.

** NCHRP Report 572: Roundabouts in the United States. National Cooperative Highway

Research Program, TRB, NAS, Washington, D.C., 2007.

Research is ongoing on additional treatments 

and design considerations to address the needs of 

visually impaired pedestrians.

> Reduce congestion

•	 Efficient during both peak hours and other times

•	 Typically less delay

> Reduce pollution and fuel use

•	 Fewer stops and hard accelerations, less

time idling

> Save money

•	 Often no signal equipment to install, power,

and maintain

•	 Smaller roundabouts may require less right-ofway than traditional intersections

•	 Often less pavement needed

> Complement other common community 

values

•	 Quieter operation

•	 Functional and aesthetically pleasing

With roundabouts, head-on and 

high-speed right angle collisions are 

virtually eliminated.

Potential vehicle conflict point