The Difference Between Maine’s Rotaries and Roundabouts

Maine has three rotaries and 22 roundabouts throughout the state. The two terms are often used interchangeably, but they shouldn't be. There is a distinct difference between rotaries and roundabouts, as each is designed for a different purpose.

Here's a Google Maps satellite view of the Augusta Memorial Circle rotary. It has two lanes in a wide circle.

And this is the roundabout in Portland at the intersections of Brighton Avenue, Deering Avenue, and Falmouth Road.  It's a tighter circle with only one lane.

So what's the difference?

According to state traffic engineer Steve Landry and CentralMaine.com:

A rotary is typically a circular roadway that has a very large radius and is built to facilitate speed going through the circle area. The way that each leg comes into the circle is kind of tangential, so you don't have to slow down a lot to enter or go around it.

 

A roundabout has a much smaller radius. As the roadways come into the circle, they're aimed to the center, forcing the motorists to take a right turn into the circle, and they're banked to naturally slow drivers down.

So there you have it. Rotaries keep you moving close to your normal speed, while roundabouts force you to slow down and are much safer than rotaries (except for when drivers do this):

If you're curious, here's a list of all the rotaries and roundabouts in Maine.

Rotaries:

Windham U.S. routes 302 and 202
Augusta Memorial Circle
Kittery U.S. Route 1 / Route 236 / State Road / Old Post Road

Roundabouts:

Sanford -  U.S. Route 202 / routes 4A and 109
Kennebunk -  Route 35 / Storer Street / Wood Point Road
South Portland -  Cottage Road / E Street / Ocean Street
Auburn Turner Street -  Lowe's
Auburn Turner Street -  Auburn Mall
Biddeford - Biddeford Crossing parking lot
Augusta - Cony Circle
Calais - Route 1 / International Avenue
Bangor -  Texas Avenue / Maine Avenue
Bangor Godfrey Boulevard - Maine Avenue
Caribou - U.S. Route 1 / North Main Street / Cary Medical Center
Gorham -  Route 114 / Gorham Bypass
Gorham  - U.S. Route 202 / Gorham Bypass
Gorham -  Route 25 / Gorham Bypass
Gorham -  U.S. Route 202 / Routes 4 and 237
Gorham -  Brackett, Libby, and Portland Roads
Bath - State Road and Congress Avenue
Orono - Stillwater and Forest Avenues
Blue Hill -  routes 15 and 172 / Beech Hill Road
Howland -  routes 6 and 116 / River Road
Augusta -  Route 3 / I-95 northbound
Augusta -  Route 3 / I-95 southbound