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FHWA Home / Safety / Proven Safety Countermeasures / Proven Safety Countermeasures - Roundabouts

Proven Safety Countermeasures

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For more information about this Proven Safety Countermeasure, visit the Office of Safety's Intersection Roundabouts and Mini Roundabouts web page.

Roundabouts

FHWA treskelion logo.
U.S. Department of Transportation
Federal Highway Administration

FHWA-SA-17-055

Icon representing a roundabout.

Roundabouts

Two-Way Stop-Controlled Intersection to a Roundabout Figure showing a two-way stop-controlled intersection converting into a roundabout.
82%

Reduction in severe crashes

Signalized Intersection to a Roundabout Figure showing a two-way stop-controlled intersection converting into a roundabout.
78%

Reduction in severe crashes

Source: Highway Safety Manual

The modern roundabout is a type of circular intersection configuration that safely and efficiently moves traffic through an intersection. Roundabouts feature channelized approaches and a center island that results in lower speeds and fewer conflict points. At roundabouts, entering traffic yields to vehicles already circulating, leading to improved operational performance.

Example of a single-lane roundabout.
Source: FHWA

Roundabouts provide substantial safety and operational benefits compared to other intersection types, most notably a reduction in severe crashes.

Roundabouts can be implemented in both urban and rural areas under a wide range of traffic conditions. They can replace signals, two-way stop controls, and all-way stop controls. Roundabouts are an effective option for managing speed and transitioning traffic from high-speed to low-speed environments, such as freeway interchange ramp terminals, and rural intersections along high-speed roads.

Example of a multi-lane roundabout.
Source: FHWA

FHWA encourages agencies to consider roundabouts during new construction and reconstruction projects as well as for existing intersections that have been identified as needing safety or operational improvements.

For more information on this and other FHWA Proven Safety Countermeasures, please visit
https://safety.fhwa.dot.gov/provencountermeasures.

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Page last modified on October 17, 2017
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Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000