What is a Roundabout?

A roundabout is a type of circular intersection, but is 

quite unlike a neighborhood traffic circle or large rotary. 

Roundabouts have been proven safer and more efficient 

than other types of circular intersections. 

Roundabouts have certain essential distinguishing features: 

• Counterclockwise Flow. Traffic travels

counterclockwise around a center island.

• Entry Yield Control. Vehicles entering the roundabout

yield to traffic already circulating.

• Low Speed. Curvature that results in lower vehicle 

speeds (15-25 mph) throughout the roundabout.

FHWA 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. They also provide significant 

operational benefits compared to conventional intersections.

Cover photo source: Google Earth Pro

ROUNDABOUTS

with Pedestrians & Bicycles

A Safe Choice for Everyone

For More Information

Jeffrey Shaw, P.E., PTOE, PTP

FHWA Office of Safety

202.738.7793 or jeffrey.shaw@dot.gov

Hillary Isebrands, P.E., PhD

FHWA Resource Center

720.545.4367 or hillary.isebrands@dot.gov

To learn more about roundabouts, please visit:

safety.fhwa.dot.gov

Publication number FHWA-SA-15-016 Updated Sept. 2020

Educational Resources

Michigan “How to Use a Roundabout – Sharing 

the Road” Informational Brochure

www.michigan.gov/documents/mdot/MDOT_

RoundaboutPedBikeBrochure_465164_7.pdf

New York Guidance for Roundabout Users

www.dot.ny.gov/main/roundabouts/guide-users/pedestrians

Washington State videos for Roundabouts and 

Pedestrians and Bicycles

www.wsdot.wa.gov/Safety/roundabouts/PedestriansCyclists.htm

Circulatory

roadway

Counterclockwise

circulation

Accessible

pedestrian crossing

Splitter Apron

island

Pavement

Markings at Entry

Landscape

buffer

Bicycle lane

treatment

Central

island

Sidewalk or

shared use

path

Figure 1. Modern Roundabout Schematic

Leveraging Partnerships

PEDSAFE Pedestrian Safety Guide &

Countermeasure Selection System - Roundabouts

www.pedbikeinfo.org/data/faq_details.cfm?id=3454 

BIKESAFE Bicycle Safety Guide & Countermeasure 

Selection System – Roundabouts

www.pedbikesafe.org/PEDSAFE/countermeasures_detail.

cfm?CM_NUM=25

Choosing Roundabouts for Safe Routes to School

www.saferoutesinfo.org/program-tools/case-study-bellingham-wa

AARP Livable Communities Fact Sheet Series

www.aarp.org/livable-communities/info-2014/livabilityfactsheet-modern-roundabouts.html

On average, roundabouts reduce severe crashes – 

those resulting in injury or loss of life – by 78-82%1

1 Highway Safety Manual, American Association of State Highway and Transportation 

Officials, Washington, DC, 2010.
CROSSWALK 

SETBACK

Source: Janet M. Barlow, Accessible Design for the Blind

Source: www.pedbikeimages.org / Dan Burden

Source: Jeffrey Shaw, FHWA

Source: City of Santa Cruz

Lower speed.

Traffic speed at any road 

or intersection is vitally 

important to the safety of 

everyone, and especially 

non-motorized users. 

Lower speed is associated 

with better yielding 

rates, reduced vehicle 

stopping distance, and 

lower risk of collision 

injury or fatality. Also, 

the speed of traffic 

through a roundabout 

is more consistent with 

comfortable bicycle

riding speed.

Source: Hillary Isebrands, FHWA

Shorter, setback crossings.

Pedestrians cross a shorter distance of only one 

direction of traffic at a time since the entering 

and exiting flows are separated. Drivers focus on 

pedestrians apart from entering, circulating and 

exiting maneuvers.

Less conflict. Roundabouts have fewer conflict

points. A single lane roundabout has 50% fewer 

pedestrian-vehicle conflict points than a comparable 

stop or signal controlled intersection. Conflicts 

between bicycles and vehicles are reduced as well.

Features for All Users. Adding certain

treatments at roundabouts can enhance the 

experience for both pedestrians and bicycles.

• At more complex roundabouts, such as those 

with multiple lanes, certain design elements 

and enhanced crossing treatments can improve 

accessibility for visually impaired pedestrians.

• Where bicycle facilities lead to a roundabout, 

providing an option to bicyclists to either ride 

in the travel lane or use a ramp to and from a 

separated shared use path.