AARoads Forum

National Boards => General Highway Talk => Traffic Control => Topic started by: Max Rockatansky on June 09, 2024, 08:47:12 PM

Title: Figure eight roundabouts
Post by: Max Rockatansky on June 09, 2024, 08:47:12 PM
Seems we don't really have a thread about figure eight roundabouts.  The announcement regarding the planned removal of one in Henderson, NV has been all the rage this weekend on Facebook.

https://www.thedrive.com/news/nevadas-figure-8-roundabout-is-being-removed-after-too-many-crashes?fbclid=IwZXh0bgNhZW0CMTEAAR0mEixNpt6hlbVjtzxBX7w7RWyuimKtKUgy40bh6jpTplvQDI3BhZdkvvU_aem_AdHFBb2FfYugFbdYutMQJBi7g4wdLD0ijzOgK4raCvfRYAj-yLLgiBTCaBmZ6j6YRpF7K0NtudoilWEY0fFxfGmH

I just posted about such a structure on Union Road in Paso Robles which was completed in June 2023:

https://m.facebook.com/story.php?story_fbid=pfbid031DGpTAvdXN25QUEEb8N7M39zmVQQYN34mH2JFhTcMAJkC956ArN9wCBApW5PsVRCl&id=100063655972258&mibextid=cr9u03
Title: Re: Figure eight roundabouts
Post by: kalvado on June 09, 2024, 09:57:11 PM
Isn't "dogbone" a general term?
Title: Re: Figure eight roundabouts
Post by: epzik8 on June 10, 2024, 07:16:37 AM
Such roundabouts would never work where I live, even though we've embraced conventional ones.
Title: Re: Figure eight roundabouts
Post by: Rothman on June 10, 2024, 07:22:46 AM
Quote from: epzik8 on June 10, 2024, 07:16:37 AMSuch roundabouts would never work where I live, even though we've embraced conventional ones.

Meh.  The way this one was implemented wouldn't work anywhere, but they can work if striped/configured as a traditional roundabout.
Title: Re: Figure eight roundabouts
Post by: kalvado on June 10, 2024, 07:30:59 AM
Quote from: epzik8 on June 10, 2024, 07:16:37 AMSuch roundabouts would never work where I live, even though we've embraced conventional ones.
These are primarily for use at diamond interchanges. Smaller than SPUI, less invasive than DDI.
Title: Re: Figure eight roundabouts
Post by: epzik8 on June 10, 2024, 08:46:03 AM
Quote from: kalvado on June 10, 2024, 07:30:59 AM
Quote from: epzik8 on June 10, 2024, 07:16:37 AMSuch roundabouts would never work where I live, even though we've embraced conventional ones.
These are primarily for use at diamond interchanges. Smaller than SPUI, less invasive than DDI.

That makes sense then.
Title: Re: Figure eight roundabouts
Post by: cjw2001 on June 10, 2024, 04:31:58 PM
No difference in rules from a "normal" roundabout.  Just flattened in one direction and stretched out a bit in the other.  If you can't understand a yield sign there is little hope for you.  And god forbid you have to drive in a curve instead of a straight line.

Meanwhile:  https://fox59.com/news/peanut-roundabout-construction-to-begin-monday-in-beech-grove/
Title: Re: Figure eight roundabouts
Post by: jakeroot on June 10, 2024, 08:06:45 PM
Quote from: cjw2001 on June 10, 2024, 04:31:58 PMMeanwhile:  https://fox59.com/news/peanut-roundabout-construction-to-begin-monday-in-beech-grove/

(https://i.imgflip.com/8tg6q3.jpg)
Title: Re: Figure eight roundabouts
Post by: Max Rockatansky on June 10, 2024, 08:23:35 PM
Dog Bone Roundabout was kind of doing something for me.
Title: Re: Figure eight roundabouts
Post by: jakeroot on June 10, 2024, 08:38:09 PM
Quote from: Rothman on June 10, 2024, 07:22:46 AM
Quote from: epzik8 on June 10, 2024, 07:16:37 AMSuch roundabouts would never work where I live, even though we've embraced conventional ones.

Meh.  The way this one was implemented wouldn't work anywhere, but they can work if striped/configured as a traditional roundabout.

It was configured as a traditional roundabout, at least when it was built in 2019. But the markings have faded, and they removed the splitter island on the eastern approach, probably ahead of reconstruction as a signalized diamond.

The only real issue as constructed is the western approach (from within the circle) is marked as a double left turn, but the inside lane is actually a U-turn, only the right lane can continue onto Via Inspirada.

Here is a quick comparison to another figure-8 roundabout in Carmel, Indiana. Pretty much identical minus the underpass, but that doesn't affect the design or operation at all:

(https://live.staticflickr.com/65535/53783497973_3fb42d6741_h.jpg)
Dogbone Roundabout Comparison (https://flic.kr/p/2pWEuac) by Jacob Root (https://www.flickr.com/photos/62537709@N03/), on Flickr

Quote from: Max Rockatansky on June 10, 2024, 08:23:35 PMDog Bone Roundabout was kind of doing something for me.

These have long been called dogbone roundabouts, though I think that has mostly been a reference to the interchange style. Flat dogbones without flyovers or underpasses are not as common, though I think the terminology is just as apt.
Title: Re: Figure eight roundabouts
Post by: fwydriver405 on June 11, 2024, 12:08:15 PM
When Kelley Square in Worcester, MA was redesigned from one of the most high crash locations in MA into a hybrid rotary/roundabout from Oct 2019 to around 2021-ish, I remember officials calling the new rotary as a "peanut".

I think this is the first and one and only kind in Massachusetts, if not the entirety of New England until very recently. If my memory serves right, they also tried putting one in Inman Square (https://www.kittelson.com/work/test-inman-square-intersection/) in Cambridge, but that was rejected into the present condition we have now (https://www.youtube.com/watch?v=cetyQjQwVpY). New Haven, CT at Yale Avenue and Chapel Street just finished their peanut roundabout sometime in early 2023.

KELLEY SQUARE:
Existing Conditions, 31 Oct 2018 during the PM Rush:

Present Condition:
Worcester's Kelley Square Reimagined | VHB (https://www.vhb.com/news/kelley-square-worcester-redesign-features-innovative-hybrid-roundabout/)


NEW HAVEN, CT
Dangerous New Haven intersection gets a 'peanut' to boost safety (https://www.nhregister.com/news/article/new-haven-builds-peanut-roundabout-to-calm-traffic-17786070.php)

Work Begins On Peanut Roundabout (https://www.newhavenindependent.org/article/work_begins_on_peanut_roundabout)
Title: Re: Figure eight roundabouts
Post by: LilianaUwU on June 13, 2024, 06:12:48 PM
Those are neither figure eights nor roundabouts.
Title: Re: Figure eight roundabouts
Post by: epzik8 on June 13, 2024, 08:27:52 PM
Quote from: fwydriver405 on June 11, 2024, 12:08:15 PMI remember officials calling the new rotary as a "peanut".

That's a new one for me, and I thought I'd heard every term in the book.
Title: Re: Figure eight roundabouts
Post by: Bobby5280 on June 13, 2024, 09:19:23 PM
The terms dogbone and peanut are logical. The figure eight term implies traffic crisscrossing in the middle, which makes me wonder if a DDI could be called a figure-16 roundabout.
:awesomeface:
Title: Re: Figure eight roundabouts
Post by: kalvado on June 13, 2024, 09:45:05 PM
Quote from: Bobby5280 on June 13, 2024, 09:19:23 PMThe terms dogbone and peanut are logical. The figure eight term implies traffic crisscrossing in the middle, which makes me wonder if a DDI could be called a figure-16 roundabout.
:awesomeface:
DNA-like roundabout sounds fancier
Title: Re: Figure eight roundabouts
Post by: NJRoadfan on June 13, 2024, 09:54:16 PM
Meanwhile in New Jersey..... https://maps.app.goo.gl/h9MeN2uvKDBHWCEe8
Title: Re: Figure eight roundabouts
Post by: Bobby5280 on June 13, 2024, 10:19:18 PM
Would that be a "figure 12" roundabout? :D
Title: Re: Figure eight roundabouts
Post by: jeffandnicole on June 14, 2024, 12:00:37 AM
Quote from: NJRoadfan on June 13, 2024, 09:54:16 PMMeanwhile in New Jersey..... https://maps.app.goo.gl/h9MeN2uvKDBHWCEe8

And in typical NJ fashion, this is considered a Traffic Circle, not a Roundabout, and on some approaches the advisory speed is an unusually high 40 mph. https://maps.app.goo.gl/3MDQdKY2dHRmXccx5 , https://maps.app.goo.gl/qpK4517X8bygTH6n6
Title: Re: Figure eight roundabouts
Post by: Rothman on June 14, 2024, 12:11:29 AM
Quote from: epzik8 on June 13, 2024, 08:27:52 PM
Quote from: fwydriver405 on June 11, 2024, 12:08:15 PMI remember officials calling the new rotary as a "peanut".

That's a new one for me, and I thought I'd heard every term in the book.

Pfft.  NYSDOT has had a peanut roundabout planned in Central Square for quite a while now.
Title: Re: Figure eight roundabouts
Post by: GaryV on June 14, 2024, 06:39:27 AM
Quote from: LilianaUwU on June 13, 2024, 06:12:48 PMThose are neither figure eights nor roundabouts.

My first thought was this: https://en.wikipedia.org/wiki/Figure_8_racing
Title: Re: Figure eight roundabouts
Post by: kalvado on June 14, 2024, 06:43:33 AM
Quote from: Rothman on June 14, 2024, 12:11:29 AM
Quote from: epzik8 on June 13, 2024, 08:27:52 PM
Quote from: fwydriver405 on June 11, 2024, 12:08:15 PMI remember officials calling the new rotary as a "peanut".

That's a new one for me, and I thought I'd heard every term in the book.

Pfft.  NYSDOT has had a peanut roundabout planned in Central Square for quite a while now.
Jumping above their paygrade yet again?
Title: Re: Figure eight roundabouts
Post by: ErmineNotyours on June 19, 2024, 02:54:14 AM