Largest Roundabouts in America

[tradephoric]

Large multi-lane roundabouts seem to becoming more commonplace in America.  I can think of a number of 3-lane roundabouts (at least partial) in Metro Detroit alone:

-Maple & Drake in West Bloomfield
-Maple & Farmington in West Bloomfield
-14 Mile & Farmington in West Bloomfield
-18 1/2 Mile & Van Dyke in Sterling Heights.
-M-5 & Pontiac Trail/Martin Road in Commerce Township.

The roundabout at M-5 & Pontiac Trail was recently completed in November 2011.  The roundabout is at the terminus point of M-5 which is a major freeway in Metro Detroit.  It is a partial 3-lane roundabout and has slip lanes at two of its legs.  The pre-roundabout counts for this intersection was 54,000 vehicles per day.

What are some other large roundabouts that have been built?  I'd be really interested in finding out which modern roundabout has the highest AADT in America.

[tradephoric]

Here's a Google KMZ file that shows the locations of roundabouts in America & Canada.  This data is probably 3 years old and doesn't include a lot of recently built roundabouts.

http://www.mediafire.com/?oooty22otn862r7

[Zmapper]

 

Where did they get all that information? Zooming in, I even see roundabouts in apartment complexes included!

[tradephoric]

I just did some quick google searches for that states that didn't show a roundabout placemark.  Found at least one example of a modern roundabout in all 50 states.

[PHLBOS]

In Massachusetts, they're called rotaries and the state has had them for decades.  The northeastern end of Route 128 has a couple rotary intersections: one at Route 127 just east of the Annisquam River Bridge (locally known as Grant Circle) the other is located about a mile east called Blackburn Circle.  Both have been there since the highway was built in the 1950s.

[SignBridge]

How about the one at Jones Beach on Long Island? Built in the 1920's, where the Wantagh and Ocean Parkways meet.  3 lanes around. In the middle sits a tall monument which is actually a water tower that can be seen from miles around.

[roadfro]

In Massachusetts, they're called rotaries and the state has had them for decades.  The northeastern end of Route 128 has a couple rotary intersections: one at Route 127 just east of the Annisquam River Bridge (locally known as Grant Circle) the other is located about a mile east called Blackburn Circle.  Both have been there since the highway was built in the 1950s.

A roundabout is a distinct type traffic circle with specific design characteristics. The rotaries you mentioned on Route 128 are not roundabouts.

How about the one at Jones Beach on Long Island? Built in the 1920's, where the Wantagh and Ocean Parkways meet.  3 lanes around. In the middle sits a tall monument which is actually a water tower that can be seen from miles around.

This appears to be an older traffic circle which was re-striped to function as a large roundabout. Lots of pavement hatching marks used here to denote pavement not to be driven on. Also, a unique striping at the "intersections" using long dashed lines to guide exiting traffic but short "cat track" dotted marks to guide entering traffic...not standard, but I like it.

[SignBridge]

Roadfro, the Jones Beach circle is actually more confusing to drive thru now, than it was before they made it so organized. (chuckle!) The original less formal striping configuration was much simpler.

[Alps]

Roadfro, the Jones Beach circle is actually more confusing to drive thru now, than it was before they made it so organized. (chuckle!) The original less formal striping configuration was much simpler.

True, unless you're there during one of the times when you have all sorts of traffic entering. In the dead of fall, winter, or spring, no markings was easier.

[JCinSummerfield]

Largest roundabout I've seen is I-270 around Columbus. 

[NE2]

Largest roundabout I've seen is I-270 around Columbus. 

Har har. I-275 around Cinci is bigger and looks like Snoopy's head.

[texaskdog]

http://www.youtube.com/watch?v=Xql99I1VSdI