Safety and Traffic Engineering

Roundabouts for Rhode Island

Making Rhode Island's roads safer is one of our primary missions. Of particular concern is safety at intersections, where 7,000 people are killed and nearly 1 million people are injured in intersection-related crashes across the country. Using modern roundabouts in place of traditional intersections is a safer solution we're looking to employ wherever we can.

What's a Roundabout?

A roundabout is a one-way, circular intersection built with no traffic signal equipment. Traffic flows around a center island, with those entering the circle yielding to traffic already in the roundabout. Get more information on how to use a roundabout.

These types of intersections generally are less expensive to operate in the long term as compared with conventional intersections, since they don't require traffic signals. This means no maintenance or electricity costs; an average savings of about $5,000 per year, per intersection.

Roundabouts are also good for pedestrians and the environment. The lower speeds and center islands make it easier to cross the street. And with no cars idling at red lights, the continuous flow of traffic means less gas wasted and less pollution.

Simply put, they are the most efficient and safest type of intersection we can build.

Safer by Design

Roundabouts have proven to reduce fatalities by 90 percent, and greatly reduce injuries and the severity of crashes. With their lower speeds, these intersections are safer for pedestrians, cyclists, older drivers and novice drivers.

A single-lane roundabout only has eight "points of conflict" where a crash could occur. Typical intersections have 32. Click on the image at right to enlarge.

Roundabouts vs. Rotaries

Roundabouts aren't the rotaries of the past. Rotaries are often much larger, sometimes using traffic signals or stop signs, with vehicles traveling at higher speeds. Roundabouts are smaller, and have a sharper angle of entry, which reduces speeds and increases safety. Here's a quick breakdown on the differences between the two:

  Size Speed Angle of Entry Who has the Right of Way?
Modern Roundabouts 150' to 230' 15 to 25 mph Sharper curve at entry; forces cars to reduce speed Vehicles in the roundabout; everyone entering must slow down and yield
Old Traffic Circles/Rotaries 600' or more 30 to 35 mph Smoother curve means cars enter circle at higher speeds Vehicles entering the circle; some have stop signs

Interactive | Media

Features of a Modern Roundabout

Interactive Tour of R.I.'s Roundabouts
Roundabout Story Map

Additional Information

How do I use a roundabout?

Using a roundabout is easy! Traffic flows continuously and always to the right. Just remember to choose your lane before you approach the circle - just like you would in a conventional intersection. Learn More ».

Friendly to Trucks and Other Large Vehicles

All roundabouts are designed with an "apron" around the center island that is flush or nearly so with the driving surface.

Cars don't drive in this area, but trucks can, allowing the largest tractor trailers, fire trucks, campers and other large vehicles to easily navigate through the circle.

The apron is often made of decorative materials such as stamped croncrete or pavers, improving the appearance of the roundabout.

Check out this video showing how trucks - even those with oversized loads - can navigate through a roundabout