AARoads Forum

Are there any roundabout junctions outside of New England?
Kinds like these

http://maps.google.com/maps?hl=en&q=I93&ie=UTF8&ll=42.419607,-71.103108&spn=0.010201,0.019312&z=16 (http://maps.google.com/maps?hl=en&q=I93&ie=UTF8&ll=42.419607,-71.103108&spn=0.010201,0.019312&z=16)

I love these, but I havnt seen these outside of New England in this country

Not that I've seen... They're the same basic design as a SPUI, which seems to be preferred around here.

there are a couple down here in San Diego.  In La Jolla, to be specific.  I also see them sporadically elsewhere.

they're huge in Europe of course.

U.S. 61 and Causeway Boulevard, one of my all time favorite interchanges

(//www.aaroads.com/forum_images/southeast/us-061_nb_at_causeway_bl.jpg)

Taken 11/20/08.

I've seen a conventional diamond with roundabouts at the ends in Colorado, I-70 Exit 168.

Quote from: Darkangel on January 20, 2009, 12:08:18 AM
I've seen a conventional diamond with roundabouts at the ends in Colorado, I-70 Exit 168.

You mean this one  :):

(https://www.aaroads.com/west/colorado070/i-070_wb_exit_167_04.jpg)

Those ones are dumbbells, they are also in Ohio and other places. The only time I've seen the one rawr_apples talked about is in this thread and SC4.

I thought they were called dogbones...  :-/

Yeah I think they are also called that. Who knew, but they are also popular in Ireland. Oh yeah, and before I forget, exit 168 is part of a great road described here (http://www.teachamerica.com/roundabouts/RA052C_Avon.pdf)

ive heard both, but dumbbells is more prevelent I think. and theyre not really like SPUI's, not by a longshot.

The one you posted is the same basic concept, if you think of a roundabout as a type of intersection.

Still dont get how theyre alike. Roundabouts allow traffic to keep going, and to give way of other cars. SPUI's require all vehicles to stop at certain points

I'm talking about the actual interchange. You get off the ramp in the same place regardless of whether it's a SPUI or roundabout.

I know what he's talking about. There are some in the US, but can't think of where. It's a roundabout placed right on top of an interchange, with the exit ramps leading onto it.

I'm saying that both roundabout interchanges like the one rawr posted in the link at the top of the page and SPUIs like this one (http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=q5919t8mzx9t&style=b&lvl=1&tilt=-90&dir=0&alt=-1000&scene=23588513&phx=0&phy=0&phscl=1&encType=1) (that I drove through a lot.. I used to live off that exit) are exactly identical except for the type of intersection on the bottom. Sorry to confuse anyone.

As for the interchange you mentioned voyager, I actually built one of those a while back in SimCity: Actually, I converted it to a diamond and don't have a pic of the original, but here's one from a SC friend: http://img254.imageshack.us/img254/228/southclearviewoct241512sk8.jpg I've heard it called a volleyball too.

Here you go: http://www.kurumi.com/roads/interchanges/volleyball.html

Ahh... kurumi! I have that bookmarked.  :banghead: Why didn't I look there...

There are two volleyballs that I know of: I-476 and U.S. 1 - http://www.northeastroads.com/pennsylvania001/us-001_nb_at_i-476_01.jpg and Interstate 240 at U.S. 70 - http://www.southeastroads.com/north_carolina050/us-070_wb_at_i-240_01.jpg. Both don't belong to this thread though.  :banghead:

Do you know what they're talking about with the roundabout mounted onto an interchange?

I'm getting confused now...  :-/ So I think it's best to make this my last post on this thread for now.

Here is a proper example of what im talking about, this one is in the UK

http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=skx0qzh0x4cg&style=b&lvl=1&tilt=-90&dir=0&alt=-1000&scene=7715118&phx=0&phy=0&phscl=1&encType=1

Yeah, they have a few of those in the US.

Just saying, I've never seen them outside of the North East though..there is one in Arlington,VA

Well the original post was about the rotary based interchanges that are found in New England.

(//www.aaroads.com/forum_images/northeast/i-093_at_willard_st.jpg)

Interstate 93 at Willard Street in Quincy, MA.

The twin-roundabout interchange was mentioned later in the thread, which incorporates roundabouts in place of intersections at the end of the respective off/on-ramps in a conventional diamond interchange.

(//www.aaroads.com/forum_images/mid-atlantic/md-100_at_meadowbridge_rd.jpg)

Maryland 100 Freeway at Meadowbridge Road

Quote from: agentsteel53 on January 20, 2009, 12:01:35 AM
they're huge in Europe of course.

Yeah, I had to negotiate 5 roundabouts to drive 1.5 miles in my former neighborhood. I hate them now, there are way too much of them in the Netherlands. They're extremely safe though, due to the slow speed, deadly collisions are rare.

Quote from: agentsteel53 on January 20, 2009, 12:01:35 AMthey're huge in Europe of course.

Very true. Can be annoying at times, but then again, we occasionally are also graced with quite a few nicely designed ones, like this one on the A26 near Stade, Germany (opened around 3 months ago):
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi285.photobucket.com%2Falbums%2Fll41%2FDAL764%2FCars%2FASStade.jpg&hash=e22ffd5da77cb3157f83c41b52a2805a5e99bf9a)
Wouldn't mind if they build more roundabouts like that :) .

^^ That's not really a classic roundabout, more like a traffic circle.

Dutch rotondomania:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.autorij-instructie.nl%2Fwp-content%2Fuploads%2F2008%2F02%2Frotonde.bmp&hash=41795a386b8bc90bd84d7917850129101358848c)

Never seen a roundabout interchange. It's very cool looking.

But there are a few roundabout intersections in Metro Atlanta. I wish that there were more.

US 15/NY 17 (now US 15/I-86) was one at one time (pic (http://terraserver-usa.com/image.aspx?T=2&S=11&Z=18&X=816&Y=11672&W=1)).  It was converted to a diamond, and now has been converted a second time to a T interchange in anticipation of I-99.

Funny I mentioned the same U.S. 15/NY-17 interchange in the Interstate 99 thread (https://www.aaroads.com/forum/index.php?topic=58.0).  :D

how about this one from the Henry Hudson Parkway (New York City) in the late 30s?

http://www.nyc-architecture.com/SPEC/088.jpg (http://www.nyc-architecture.com/SPEC/088.jpg)

There's a few in New york, mainly along the coastline freeways i've noticed though

There is also a 3-level stacked in New Orleans
http://maps.google.com/maps?hl=en&q=new+orleans,+la&ie=UTF8&split=0&gl=us&ll=29.973905,-90.155879&spn=0.005985,0.009656&t=k&z=17 (http://maps.google.com/maps?hl=en&q=new+orleans,+la&ie=UTF8&split=0&gl=us&ll=29.973905,-90.155879&spn=0.005985,0.009656&t=k&z=17)

Farthest i've seen out of New England

Quote from: rawr apples on January 27, 2009, 02:31:42 AM
There's a few in New york, mainly along the coastline freeways i've noticed though

There is also a 3-level stacked in New Orleans
http://maps.google.com/maps?hl=en&q=new+orleans,+la&ie=UTF8&split=0&gl=us&ll=29.973905,-90.155879&spn=0.005985,0.009656&t=k&z=17 (http://maps.google.com/maps?hl=en&q=new+orleans,+la&ie=UTF8&split=0&gl=us&ll=29.973905,-90.155879&spn=0.005985,0.009656&t=k&z=17)

Farthest i've seen out of New England

Thats the same interchange I posted a photo of on the first page of this thread.  :-D

Quote from: Chris on January 22, 2009, 04:40:01 PM
^^ That's not really a classic roundabout, more like a traffic circle.

I've never really understood the difference...

Traffic circles can also be traffic-light controlled.

Quote from: aaroads on January 20, 2009, 12:02:25 AM
U.S. 61 and Causeway Boulevard, one of my all time favorite interchanges

(//www.aaroads.com/forum_images/southeast/us-061_nb_at_causeway_bl.jpg)

Taken 11/20/08.

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.fileden.com%2Ffiles%2F2008%2F10%2F16%2F2145144%2FNO2.jpg&hash=df6edae8bb51fa585e9862f879886c68794fcc41)

ah did not notice :-D

looks pretty cool from the road. so big.

Hmmm, looks like a vollyball except with a traffic circle. It looks like it would move traffic, but who knows.

West 70th Street in Edina, MN had 3 roundabouts installed last summer.

How about the magic roundabout...

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F1%2F13%2FSwindon_Magic_Roundabout_eng.png&hash=3a557fa1a9eea22918bb44b0732ccaf9af05f048)

Thats a bit much for the average american to even comprehend. they can barely get regular roundabout

The "Magic Roundabout" looks complex, but fun to drive.


Be well,

Bryant

Quote from: rawr apples on February 01, 2009, 03:57:43 AM
Thats a bit much for the average american to even comprehend. they can barely get regular roundabout

I think that nobody who doesn't drive there regularly can comprehend such roundabouts.

Quote from: ComputerGuy on January 31, 2009, 11:56:35 PM
How about the magic roundabout...

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F1%2F13%2FSwindon_Magic_Roundabout_eng.png&hash=3a557fa1a9eea22918bb44b0732ccaf9af05f048)

Wow, I actually get it. I had to stare at it for about 5 min., but I get it.  I agree that is too much for the average American to handle.

Yeah...first of all, the cars are flowing in the opposite direction from America, second we don't have 8 mini-roundabouts inside one huge one.

Gotta love the British  ;-)

Quote from: NOLANOLA504 on February 01, 2009, 11:35:09 AMI agree that is too much for the average American to handle.

Not just the average American, pretty much every average non-Brit  ;-) . Granted, I have figured out how it's supposed to work, but actually driving up to that roundabout and be faced with the quest of having to chose the right turns would be a whole different story  :-/.

Here's a video of an American roundabout, located in Douglas County, Georgia. This roundabout is located at the intersection of SR 5 and SR 166, eighteen miles or so west of Atlanta.

Roundabout appears 4:21 into the video.

http://www.youtube.com/watch?v=Qi3paqc8Blk (http://www.youtube.com/watch?v=Qi3paqc8Blk)

Be well,

Bryant

WSDOT has an instructional video:

http://www.wsdot.wa.gov/eesc/CAE/designvisualization/video/Portfolio/Modern_Roundabouts/mpg_index.htm (http://www.wsdot.wa.gov/eesc/CAE/designvisualization/video/Portfolio/Modern_Roundabouts/mpg_index.htm)

I make a point of driving through roundabouts whenever im driving near one..driving on I-70 in colorado I exited at almost every ski-town with roundabout junctions. my mum wasnt very understanding.

You can see me negotiate a bunch of roundabouts in this video.

Taken in a new neighborhood of my city.
http://nl.youtube.com/watch?v=likZwFiisGs&ap=%2526fmt%3D18 (http://nl.youtube.com/watch?v=likZwFiisGs&ap=%2526fmt%3D18)

Here are two videos that I made of some roundabout junctions: the top video is located in Douglas County, Georgia and the bottom video is located in Southwest Atlanta.

http://www.youtube.com/watch?v=hNdHolB_59M (http://www.youtube.com/watch?v=hNdHolB_59M)

http://www.youtube.com/watch?v=LVD2g74p3mI (http://www.youtube.com/watch?v=LVD2g74p3mI)


Be Well,

Bryant

Quote from: aaroads on January 20, 2009, 12:02:25 AM
U.S. 61 and Causeway Boulevard, one of my all time favorite interchanges

At night it's even more spectacular, all the brownish-yellow lights illuminate it like a Christmas tree.

Constructed 1959; a living symbol of Jefferson Parish: from shining and gleaming with the first suburban growth wave to the semi-dilapidated condition of today, mirroring East Jefferson's current first generation suburban decay.

Interestingly, it has never borne a name, even an official one so far as I know. Folks in New Orleans just call it "Causeway and Airline" or some such. My proposed name for it would be the "Shrewsbury Four Level." In the photo all levels - Airline Hwy. underpass, railroad, elevated roundabout, Causeway Blvd. viaduct - can be observed at once.

Quote from: ComputerGuy on February 01, 2009, 07:50:27 PM
WSDOT has an instructional video:

http://www.wsdot.wa.gov/eesc/CAE/designvisualization/video/Portfolio/Modern_Roundabouts/mpg_index.htm (http://www.wsdot.wa.gov/eesc/CAE/designvisualization/video/Portfolio/Modern_Roundabouts/mpg_index.htm)

I couldn't help but laugh at that video the first time I saw it.  The very fact that various transportation agencies here in the US are making instructional videos to show people how to drive roundabouts speaks loads to how many folks here just don't get roundabouts.

-Alex (Tarkus)

I always think those are an insult to my intelligence

Click the link below to access a site about the "modern roundabout," presented by the Arizona Department of Transportation.

http://www.dot.state.az.us/CCPartnerships/Roundabouts/index.asp (http://www.dot.state.az.us/CCPartnerships/Roundabouts/index.asp)


Be well,

Bryant

I also hate that they slabbed the word 'modern' onto it.  I hate that word. of any usage

Quote from: Urban Prairie Schooner on February 03, 2009, 09:04:24 PM

Quote from: aaroads on January 20, 2009, 12:02:25 AM
U.S. 61 and Causeway Boulevard, one of my all time favorite interchanges

At night it's even more spectacular, all the brownish-yellow lights illuminate it like a Christmas tree.

Years ago Andy and I decided to try out the tripod at night within the interchange:

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.southeastroads.com%2Flouisiana050%2Fus-061_sb_at_causeway_bl_03.jpg&hash=72fea4900db54cee4b8bf9a6f3d14f8a89988385)

And I totally agree with the statement you made above.

Kansas is becoming quite fond of the stupid things, much to my chagrin; KDOT loves to construct them not just at "normal" places like urban areas and near freeway interchanges but also at random highway intersections in the middle of nowhere. Imagine driving along at 65 MPH for a few dozen miles and randomly being dumped into one. Bit jarring.

Has any1 mentioned about the twin roundabout interchange on I-87 @ NY 67 in Malta, NY? On NY 67 in Malta, NY, there are about 5 roundabouts in a row! Lookee here:
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Malta,+NY&sll=37.0625,-95.677068&sspn=42.089199,92.8125&ie=UTF8&ll=42.970461,-73.800852&spn=0.00953,0.022659&t=h&z=16 (http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Malta,+NY&sll=37.0625,-95.677068&sspn=42.089199,92.8125&ie=UTF8&ll=42.970461,-73.800852&spn=0.00953,0.022659&t=h&z=16)

Also note Googles little route shield error to the right. It is signed as a state route 9 when should be US 9!

ic

Quote from: Scott5114 on February 04, 2009, 06:08:17 AM
Kansas is becoming quite fond of the stupid things, much to my chagrin; KDOT loves to construct them not just at "normal" places like urban areas and near freeway interchanges but also at random highway intersections in the middle of nowhere. Imagine driving along at 65 MPH for a few dozen miles and randomly being dumped into one. Bit jarring.

sounds like New York :-P

Carmel, Indiana, a northern suburb of Indianapolis, likely is the Roundabout capital of the Midwest. The city has about 50 of them installed a many interchanges and is currently upgrading Keystone Ave. (former Indiana 431) into a parkway that has the dumbell roundabout interchanges at each junction. The trend is showing up up in other Indy suburbs as well, although the most famous one is the Monument Circle in the center of downtown Indy, though that is more of a traffic circle than a roundabout.

Here's a video of how a roundabout works, presented by the Missouri Department of Transportion (MoDot).

http://www.youtube.com/watch?v=b2x8OI5ixRg&eurl=http://www.modot.mo.gov/central/major_projects/roundabout.htm (http://www.youtube.com/watch?v=b2x8OI5ixRg&eurl=http://www.modot.mo.gov/central/major_projects/roundabout.htm)

Also, here's a brochure about roundabouts.

http://www.modot.mo.gov/central/major_projects/documents/233.3_DrivingtheRoundaboutWay.pdf (http://www.modot.mo.gov/central/major_projects/documents/233.3_DrivingtheRoundaboutWay.pdf)


Be well,

Bryant

Quote from: tdindy88 on February 11, 2009, 02:54:21 PM
Carmel, Indiana, a northern suburb of Indianapolis, likely is the Roundabout capital of the Midwest.

Thanks for the tip, I'll check them out on Google Earth. I am so used to roundabouts, I think I drove across like 15 or 20 today...

http://maps.google.com/maps?hl=en&q=I93&ie=UTF8&ll=42.505658,-83.75821&spn=0.004398,0.013733&t=h&z=17 (http://maps.google.com/maps?hl=en&q=I93&ie=UTF8&ll=42.505658,-83.75821&spn=0.004398,0.013733&t=h&z=17)

A roundabout near where i live.

Here's a roundabout junction in Santa Barbara (northbound only on the freeway), where Route 144 ends at US 101:
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=S+Milpas+St+%26+Carpinteria+St,+Santa+Barbara,+CA&sll=34.421217,-119.676996&sspn=0.00316,0.004737&ie=UTF8&ll=34.421036,-119.676057&spn=0.006319,0.009474&t=h&z=17 (http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=S+Milpas+St+%26+Carpinteria+St,+Santa+Barbara,+CA&sll=34.421217,-119.676996&sspn=0.00316,0.004737&ie=UTF8&ll=34.421036,-119.676057&spn=0.006319,0.009474&t=h&z=17)

And a true (non-roundabout) volleyball in Calgary, AB that I went through back in 1993:
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=1801+16+Ave+NE,+Calgary,+AB&sll=51.06659,-114.024836&sspn=0.004814,0.009474&ie=UTF8&t=h&z=16&iwloc=addr (http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=1801+16+Ave+NE,+Calgary,+AB&sll=51.06659,-114.024836&sspn=0.004814,0.009474&ie=UTF8&t=h&z=16&iwloc=addr)

Quote from: NOLANOLA504 on January 31, 2009, 12:46:46 PM

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.fileden.com%2Ffiles%2F2008%2F10%2F16%2F2145144%2FNO2.jpg&hash=df6edae8bb51fa585e9862f879886c68794fcc41)

Quote from: John on January 31, 2009, 02:04:25 PM

Hmmm, looks like a vollyball except with a traffic circle. It looks like it would move traffic, but who knows.

It depends where they're used and how much turning traffic there is. We have some here in the UK at the junction of major freeways and they cause havoc because the turning movements are not freeflow. Most of them have had traffic lights fitted at all the approaches but this still doesn't solve the lack of capacity. One of them now has direct connectors added for two of the movements in addition to the traffic lights but it's still plauged by heavy traffic.

The two roundabouts of Marysville:

Tulalip: Quil Ceda Boulevard at 34th Avenue (http://maps.google.com/maps?f=d&source=s_d&saddr=48.106328,-122.186036&daddr=&hl=en&geocode=&mra=mi&mrsp=0&sz=16&sll=48.104909,-122.183461&sspn=0.008124,0.016479&ie=UTF8&ll=48.106357,-122.185199&spn=0.008124,0.016479&z=16)
Shoulets: Shoulets Road at 51st Avenue / 108th Avenue (http://maps.google.com/maps?f=d&source=s_d&saddr=48.092728,-122.162551&daddr=&hl=en&geocode=&mra=mi&mrsp=0&sz=18&sll=48.092739,-122.16254&sspn=0.002032,0.00412&ie=UTF8&z=18)

Here's a better photo of the roundabout at the intersection of S.R. 5 and S.R 166, just south of Douglasville, Georgia.

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi594.photobucket.com%2Falbums%2Ftt24%2FBryant5493%2FPICT0145.jpg&hash=62249348756254a302c1cf54958596152efe8189)


Be well,

Bryant

I can think of 2 roundabouts in Michigan.  One is just south of Clare, where old US-27 junctions with BUS US-127, and the other is at old US-27 and a city street by Gaylord High School. :coffee:

They're becoming extremely common here in Wisconsin.

Mike

^^

Aren't there quite a few by Lambeau Field?


Be well,

Bryant

not yet I believe - but once the US 41 project is done there will be.

The first of two so far is under construction in Platteville on a new alignment to connect UW-Plateville to US 151.

Depending how you want to count it, in my (pretty small - 17k pop) town, there's either 6, or 23. The 23 includes mini roundabouts. Of course, that's just typical suburban/semi-rural England

Quote
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.fileden.com%2Ffiles%2F2008%2F10%2F16%2F2145144%2FNO2.jpg&hash=df6edae8bb51fa585e9862f879886c68794fcc41)

Weaving...

The above puts me in mind of a SPUI with a roundabout instead of a traffic light.

Quote from: Master son on September 18, 2010, 03:14:36 AM
not yet I believe - but once the US 41 project is done there will be.

The first of two so far is under construction in Platteville on a new alignment to connect UW-Plateville to US 151.

There is a just-completed one on Ashland Ave just off of its connection with US 41 at the north edge of De Pere.

Mike

Quote from: Scott5114 on February 04, 2009, 06:08:17 AM
Kansas is becoming quite fond of the stupid things, much to my chagrin; KDOT loves to construct them not just at "normal" places like urban areas and near freeway interchanges but also at random highway intersections in the middle of nowhere. Imagine driving along at 65 MPH for a few dozen miles and randomly being dumped into one. Bit jarring.

Same with Arizona! :pan: :banghead: :angry:

Quote from: Bryant5493 on April 12, 2009, 05:45:39 PM
Here's a better photo of the roundabout at the intersection of S.R. 5 and S.R 166, just south of Douglasville, Georgia.

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi594.photobucket.com%2Falbums%2Ftt24%2FBryant5493%2FPICT0145.jpg&hash=62249348756254a302c1cf54958596152efe8189)


Be well,

Bryant

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.ozroads.com.au%2FNSW%2FRouteNumbering%2FState%2520Routes%2F132%2F15.JPG&hash=3f8a614cba740112cd7f6c243693a4da961e2a5f)
Here is one from New South Wales, Australia. Aussies have been using roundabouts for roughly 25 years.

Quote from: hm insulators on September 28, 2010, 07:39:23 PM

Quote from: Scott5114 on February 04, 2009, 06:08:17 AM
Kansas is becoming quite fond of the stupid things, much to my chagrin; KDOT loves to construct them not just at "normal" places like urban areas and near freeway interchanges but also at random highway intersections in the middle of nowhere. Imagine driving along at 65 MPH for a few dozen miles and randomly being dumped into one. Bit jarring.

Same with Arizona! :pan: :banghead: :angry:

Is it any more jarring than coming to a stop light or stop sign? 

Quote from: jjakucyk on September 30, 2010, 12:39:07 AM

Is it any more jarring than coming to a stop light or stop sign?  

is that not jarring enough?  through traffic should not be stopped.

any interchange where mainline traffic, with a speed limit over 50 or so, has to come to a stop is a failure in design.  (well, it can be argued that any interchange where any traffic whatsoever has to come to a stop is a failure in design.  If I wanted to not be moving, I'd have stayed home!)

QuoteKansas is becoming quite fond of the stupid things, much to my chagrin; KDOT loves to construct them not just at "normal" places like urban areas and near freeway interchanges but also at random highway intersections in the middle of nowhere. Imagine driving along at 65 MPH for a few dozen miles and randomly being dumped into one. Bit jarring.

Wait, so you're saying this is unnecessary?
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.davidjcorcoran.com%2Fhighways%2Fks%2F400%2F75to47%2F5.jpg&hash=e7f29d1b8731fc07b0e69219ab6654fdb39fed01)

Quote from: agentsteel53 on September 30, 2010, 12:56:07 AM

Quote from: jjakucyk on September 30, 2010, 12:39:07 AM

Is it any more jarring than coming to a stop light or stop sign? 

is that not jarring enough?  through traffic should not be stopped.

any interchange where mainline traffic, with a speed limit over 50 or so, has to come to a stop is a failure in design.  (well, it can be argued that any interchange where any traffic whatsoever has to come to a stop is a failure in design.  If I wanted to not be moving, I'd have stayed home!)

I think there might be some confusion over freeway type roads and rural 2-lane highways.  Of course in any fairly remote area with little traffic, nobody would have to stop for a roundabout, just slow down.  If there's two relatively equal highways intersecting, one will have to give way to the other in the case of stop signs or traffic signals, so somebody is going to be "jarred" in that instance.  Besides, maybe there's a high turning volume or just a lot of traffic in general, we don't really know.  Considering the amount of engineering that goes into a roundabout, they wouldn't have put it in if there wasn't a reason for it. 

I'm fully expecting most, if not all, of the rural state highway intersections here in Wisconsin that are now controlled with signals or all-way STOP signs to become roundabouts at their next scheduled rebuilds (assuming that they are not planned to be upgraded to grade-separated interchanges) - and there are such controls at quite a few pretty major highway intersections throughout the state.

WisDOT will also likely do that at those odd junctions where the major routing makes a 90 degree turn, many of which include an obsolete non-stop curve for that turn with the other roads connecting to it with a 'T' intersection in the middle of that curve.

For example, see:
http://maps.google.com/?ie=UTF8&ll=44.351565,-88.537724&spn=0.008853,0.021973&t=k&z=16
This is a short distance northwest of Appleton, WI.  The road making the turn is WI 76, Outagamie County 'O' heads off to the right.  WisDOT just rebuilt this intersection as a roundabout, it was completed about a month ago.

I also anticipate seeing WisDOT rebuilding the decades-obsolete US 12/WI 20/WI 67 intersection between Elkhorn and Whitewater, WI
http://maps.google.com/?ie=UTF8&ll=42.799479,-88.563323&spn=0.009084,0.021973&t=k&z=16
as a roundabout within the next few years. (US 12 now makes the sharp turn there).  Even if/when WisDOT builds the proposed US 12 Elkhorn-Whitewater 'Corner Cut' freeway, this will remain an important intersection on the state highway system.

WisDOT also recently rebuilt a couple of BAD rural intersections along US 10 just southeast of Appleton (at WI 55 and at Calumet County 'N') as roundabouts.  Ditto the previously BAD intersection on a curve on WI 55 at Calumet/Outagamie County 'KK' in Kaukauna.

MANY others are coming within the next few years and the ones that now exist appear to be working well and have very good public acceptance.

Mike

I see WisDOT's adding a pair of 'em to little old Medford up north next year, thus breaching into some new territory for roundabouts in WI.  They're certainly becoming the first choice for suburban/sprawl zone arterial intersections; their best application, incidentally.

Count me as a fan.  Beats the hell out of waiting for a goddamn left turn arrow.

Quote from: triplemultiplex on October 05, 2010, 05:49:36 PM
I see WisDOT's adding a pair of 'em to little old Medford up north next year, thus breaching into some new territory for roundabouts in WI.  They're certainly becoming the first choice for suburban/sprawl zone arterial intersections; their best application, incidentally.

Count me as a fan.  Beats the hell out of waiting for a goddamn left turn arrow.

IIRC, WisDOT recently built one at either the US 2/US 63 intersection or the US 2/WI 13 (middle junction) intersection just west of Ashland, too.

A few state highway places where I'd like to see then added in Wisconsin (assuming that they have not yet been so planned or placed):

Where - (Current traffic control)
-WI 55/96 north split (Lawe/Green Bay/Delanglade Sts) in Kaukauna - (three STOP signs at a four-way intersection)
-WI 13/21 near Adams - (four-way STOP)
-WI 21/49 near Auroraville - (four-way STOP)
-US 41/WI 125 (College Ave) ramp intersections (Appleton) - (signals)
-US 41/WI 96 (Wisconsin Ave) ramp intersections (Appleton) - (signals)
-US 41/WI 15 (Northland Ave) ramp intersections (Appleton) - (signals)
-WI 441/College Ave ramp intersections (Appleton) - (signals)
-WI 441/Calumet St ramp intersections (Appleton) - (signals)
-US 10/WI 114 west split (Menasha) - (signals)
-US 10/WI 32/57 (Forest Junction) - (signals)
-WI 76/Outagamie County 'JJ' in Greenville area - (four-way STOP)
-WI 76/96 just west of Appleton - (signals)

Mike

Quote from: mgk920 on October 06, 2010, 02:27:07 AM
IIRC, WisDOT recently built one at either the US 2/US 63 intersection or the US 2/WI 13 (middle junction) intersection just west of Ashland, too.

It's the US 2/WI 13 jct west of Ashland. And it's going in next year.
http://www.dot.wisconsin.gov/projects/us2wis13/index.htm (http://www.dot.wisconsin.gov/projects/us2wis13/index.htm)

Quote from: mgk920 on October 06, 2010, 02:27:07 AM
-WI 441/College Ave ramp intersections (Appleton) - (signals)
-WI 441/Calumet St ramp intersections (Appleton) - (signals)

That would compliment the ramp terminal roundabouts WisDOT has in the works for that proposed 441 rebuild/expansion rather nicely.

Some good spots Up Nort':
All of the traffic light controlled intersections on the US 8/WI 47 & WI 17 Rhinelander bypasses
US 8 & US 45's two junctions in Monico
US 8 and Lincoln CTH's A & L
US 8 & WI 27, Ladysmith (might be a tight squeeze)
the US 51/WI 70 junctions in Woodruff

Over the past several months, I've been pondering not so much a list of specific junctions for roundabouts, but the types of intersections that would be good candidates for roundabouts.  Here's some category examples:

- Rural 2-lane/2-lane intersections with traffic signals.  Two candidate examples would be US 71/MN 7 south of Willmar, MN and US 75/US 212 south of Madison, MN.  Another example recently converted to a roundabout is US 15/US 50 at Gilbert's Corner, VA.

- Rural 2-lane/2-lane intersections with all-way stop control.  Candidate examples include MS 13/MS 28 west of Magee, MS or MS 13/MS 18 at Puckett, MS.

- Rural 4-lane/2-lane intersections with all-way stop control and no more than moderate traffic.  Specifically thinking of US 45/MS 16 in Scooba, MS and US 45/MS 14 in Macon, MS here, though US 11/US 80 near Cuba, AL is another example.

- Rural 2-lane/2-lane intersections with stop control only on one road but moderate traffic on both roads.  Especially if there's a history of accidents at the intersection.  MN 7/MN 25 west of St. Bonifacious, MN is a recent conversion.

- Interchange ramp terminals with moderate traffic.  The first roundabouts in Minnesota, at the I-35 Medford exit (Exit 48/Steele CSAH 12) fall under this category, in part due to the nearby outlet mall.  Another example built about 5 or so years ago is the then-new I-95/495 DC Beltway interchange at Richie-Marlboro Rd (Exit 13).  Using roundabouts enabled MD SHA to provide an acceptable level-of-service without having to replace the Beltway bridges over the road (which would have been needed in order to widen Richie-Marlboro Rd for left turn lanes).

You have six routes coming together - either you can have a complex signalised thing with channels and all sorts, or you can have big roundabout that's hard to get on due to speed, or you can have a Magic roundabout (http://maps.google.com/?ie=UTF8&ll=51.74704,-0.469258&spn=0,0.01929&z=16&layer=c&cbll=51.74673,-0.474292&panoid=GAPjGTqCCjxZYhRJn-r7SA&cbp=12,107.32,,0,5.7). They really aren't that hard to drive, when you realise that you just give way to the right (left in drive-on-right countries, but they don't have them). This one even has signs reminded you to give way to right. It's fun to go the 'wrong way' around them, compared to if it wasn't two way around the roundabout.

To be fair, cases where 6 routes come together are pretty rare on this side of the pond.  Not unheard of, but rare.

I know of an area with 4 of them, around Talmadge, OH.  The four six way intersections surround Talmadege with it's 8-way traffic circle in the center.

NW side: (due to terrain, this one is not a candidate for a roundabout)
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Tallmadge,+OH&sll=37.0625,-95.677068&sspn=48.555061,51.679688&ie=UTF8&hq=&hnear=Tallmadge,+Summit,+Ohio&ll=41.119097,-81.465619&spn=0.011364,0.012617&t=h&z=16

NE side:
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Tallmadge,+OH&sll=37.0625,-95.677068&sspn=48.555061,51.679688&ie=UTF8&hq=&hnear=Tallmadge,+Summit,+Ohio&ll=41.118062,-81.414742&spn=0.011364,0.012617&t=h&z=16

SE side:
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Tallmadge,+OH&sll=37.0625,-95.677068&sspn=48.555061,51.679688&ie=UTF8&hq=&hnear=Tallmadge,+Summit,+Ohio&ll=41.084155,-81.416309&spn=0.01137,0.012617&t=h&z=16

SW side:
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Tallmadge,+OH&sll=37.0625,-95.677068&sspn=48.555061,51.679688&ie=UTF8&hq=&hnear=Tallmadge,+Summit,+Ohio&ll=41.084171,-81.466992&spn=0.01137,0.012617&t=h&z=16

And the traffic circle - NOT roundabout:
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=Tallmadge,+OH&sll=37.0625,-95.677068&sspn=48.555061,51.679688&ie=UTF8&hq=&hnear=Tallmadge,+Summit,+Ohio&ll=41.101491,-81.440878&spn=0.011367,0.012617&t=h&z=16

Quote from: froggie on October 07, 2010, 09:07:20 AM
To be fair, cases where 6 routes come together are pretty rare on this side of the pond.  Not unheard of, but rare.

the one place you seem to get them a lot is Washington DC, but that is of course a 1790s layout. 

I suddenly wonder if Washington's near-miss intersections, in which two junctions (each with their own independent set of traffic signals) are separated by as little as 30-40 feet, could be improved, from a perspective of safety and efficiency, by replacing traffic signals with roundabouts. 

I know I've run a red light in Washington because one light turned green and the next one did not.  I had thought that both sets of lights were for the same intersection, and the one that was red was for some obscure branch (because the entire complex did feature 5 or 6 roads coming together), as opposed to telling me to come to a complete stop after crossing the first street and then traveling a whopping 15 feet thereafter.

In 5 or 6-way intersections like the examples above, roundabouts can actually be rather difficult to implement.  If all legs of the intersection are equally arranged around the circle it's easier, but still can be a problem.  The main issue is that to accommodate the proper entry and exit geometries of the approach legs, the circle itself needs to be enlarged.  That's a big no-no in modern roundabouts because it encourages higher speeds around the circle and thus makes it more difficult to merge into it.  

A good example of this problem is the traffic circle in Pinehurst, NC (http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=pinehurst,+nc&sll=39.16748,-84.534789&sspn=0.388088,0.624847&gl=us&ie=UTF8&hq=&hnear=Pinehurst,+Moore,+North+Carolina&ll=35.201762,-79.450486&spn=0.006391,0.009763&t=h&z=17) (note I said traffic circle, not roundabout).  It's so large you could built a modern roundabout and all its approach streets entirely within the confines of the existing circle.  Because of this, the speeds around the circle are on the order of 35 MPH, making merging in very difficult and causing long queues during busy periods.  However, notice how tight the two roads on the left (NC-211 and NC-2) are already.  To accommodate that with a smaller circle would require all the approach roads to be squished around to give more room and even then it still might be compromised.  I'm not saying it can't be done of course, but it's much much more difficult and unlikely to be implemented.  I also doubt we'd ever see a magic roundabout in this country.

Something I would hope to see more study of is the turbo roundabout. (http://img246.imageshack.us/img246/2506/turborotonde.jpg)  This is something that's pretty new to the world, but it shows a lot of promise for accommodating higher traffic volumes while eliminating the problems of a multi-lane circle (namely getting stuck on the inside lane and cutting off people on the outside lane while exiting).  It uses a pinwheel geometry to gradually throw the inside lane of the "circle" outwards, so you pick your lane before entering the junction, and never have to weave to exit.  The only real downside is that it may not allow for u-turns, and it might not accommodate more than 4 legs at all.  The one in the picture must have some really high traffic volume since it appears to be signalized (note the stop lines inside the "circle"), but I don't know the history of that one.  It isn't quite as safe as a normal modern roundabout because some of the entering traffic is crossing perpendicular to circulating traffic rather than simply merging into it.  Still, it's a compelling design, and in fact it's even in the 2009 MUTCD.  In chapter 3C, diagrams 3C-5 and 3C-12 are both full true turbo roundabouts, while some of the other diagrams have a few aspects of it, but they aren't complete.  The difference is that the pinwheel effect is done with painted lane markings rather than any hardscape geometry.

Quote from: jjakucyk on October 07, 2010, 11:30:42 AMtraffic circle in Pinehurst, NC (note I said traffic circle, not roundabout).

what is the difference?  and, while we're at it, what's a rotary?

Traffic circles and rotaries (those two terms are basically interchangeable) are typically larger, operate at higher speeds, and often give priority to entering traffic as compared to roundabouts.  They also have much more lax geometries than modern roundabouts, which can lead to unsafe merging or weaving across lanes. 

The first modern roundabout in the USA was built in 1990, so anything older than that is a traffic circle.  Some old traffic circles have had their geometries improved where possible, and most cases where the circulating traffic had to yield to entering traffic has been corrected, because it would easily cause the circle to lock up.  They're still likely to have an overly large circle and thus higher speeds than desired.  It's a case where higher speed results in lower capacity, which seems counterintuitive, but that's how it really works.

Quote from: jjakucyk on October 07, 2010, 11:30:42 AM
In 5 or 6-way intersections like the examples above, roundabouts can actually be rather difficult to implement.  If all legs of the intersection are equally arranged around the circle it's easier, but still can be a problem.  The main issue is that to accommodate the proper entry and exit geometries of the approach legs, the circle itself needs to be enlarged.  That's a big no-no in modern roundabouts because it encourages higher speeds around the circle and thus makes it more difficult to merge into it.

In the UK, people don't seem to have that much of a problem with roundabouts with high circulatory speeds. There's quite a few, normally at freeway intersections, or in new build towns, where you can get up to 30-40mph easily (there's one in Skelmersdale which is a mile around and you can easily do the 60mph speed limit, but also no traffic), but the merging is normally OK on these big roundabouts, depending on traffic levels. The Pyebush roundabout in Beaconsfield (http://maps.google.com/?ie=UTF8&ll=51.601423,-0.623742&spn=0.002709,0.004823&t=h&z=18) has a large radius (by no means the largest) and traffic heads round it at 40mph, it's fairly heavily trafficked, but people don't seem to have trouble getting onto it.

OK, many large roundabouts have been signalised, like the turbo roundabout, only with less channelisation (one or two have colour coding to make it easier to follow the spiral pattern, and u-turns aren't too difficult, or having 5 or 6 exits), or have been turned into magic roundabouts, like the example I gave. Of course, I never suggested a roundabout for 5- or 6-way junctions, I suggested magic roundabouts for them.

Here's a turbo roundabout, UK style (http://maps.google.com/?ie=UTF8&ll=53.549462,-2.259997&spn=0.005182,0.009645&t=k&z=17). It's in a place that ought to have some kind of stack and it struggles with traffic levels, but it has also (unlike almost everywhere) got colour-coding for the right turns - red for E to N, green for S to E, yellow for W to S and grey (lighter than the tarmac) for N to W. Here's a version with 7 roads, and no colour coding (http://maps.google.com/?ie=UTF8&ll=51.527035,-3.240259&spn=0.010853,0.01929&t=k&z=16) - this (1.3 miles around, IIRC) didn't use to be signal controlled, but it, again, ought to have some free-flow ramps due to traffic levels and the roundabout doesn't give enough capacity without signals. One of the entrances is still a yield. There's probably a better example than that second one, but it shows a couple of points - that you can have more than 4 entrances, and you can have yields onto high speed roundabouts and not have much problem.

What's an old roundabout? Traffic Circle? I'm just confused as modern roundabout seems to just be a plain vanilla, small roundabout - nothing modern about them, just that they are only 30 years old in America.

Quote from: agentsteel53 on October 07, 2010, 01:14:34 PMwhat is the difference?  and, while we're at it, what's a rotary?

Traffic circles are yield to traffic entering, Roundabouts are yield on entrance. That is the difference, not geometry or size. Unless this is a US English/UK English discrepancy.

Traffic circle is mostly a US term, but regardless the distinction is definitely more than just who gives way, geometry and size are a big part of it too.  The Wikipedia article explains all the differences pretty well:  http://en.wikipedia.org/wiki/Roundabout

Here's (http://maps.google.co.uk/?ie=UTF8&t=k&ll=58.434593,15.530033&spn=0.01732,0.055747&z=15) an example in Sweden where there's no yield or stop lines. You'll need to zoom in to see the markings properly but the entrances/exits are treated as lane gains/drops, possibly with similar weaving to that in cloverleafs.

Quote from: jjakucyk on October 07, 2010, 01:46:37 PMTraffic circle is mostly a US term, but regardless the distinction is definitely more than just who gives way, geometry and size are a big part of it too.  The Wikipedia article explains all the differences pretty well:  http://en.wikipedia.org/wiki/Roundabout

It's a US/UK difference then (with wikipedia written by Americans) - we have some traffic circles (with priority on entry), but big fast things are roundabouts if you give way on entry or used to, before they put up traffic lights.

this better be signed explicitly with a yield sign, because goodness knows I'm not going to remember who has to yield to whom when I approach a State of Ohio Officially Approved Cyclic Traffic Interchange Mechanism, after crossing in from Indiana, where their Indiana Toll Road Authority Circumferential Vehicle Distribution Interface had a completely different set of rules.

Of course there's a yield sign.

Quote from: jjakucyk on October 07, 2010, 03:09:59 PM
Of course there's a yield sign.

I'd prefer two, honestly.  One yield sign at the gore point of an on-ramp, if rotated ever so slightly, flips its meaning completely.

Roundabouts...

* A new one was completed earlier this year in Hammond, La. at La. 3158 and Old Covington Highway (secretly signed La. 1067)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fmaps.google.com%2Fmaps%3Fq%3Dhammond%2C%2Bla%26amp%3Boe%3Dutf-8%26amp%3Bclient%3Dfirefox-a%26amp%3Bie%3DUTF8%26amp%3Bhq%3D%26amp%3Bhnear%3DHammond%2C%2BTangipahoa%2C%2BLouisiana%26amp%3Bgl%3Dus%26amp%3Bei%3D2t6zTIvlJYWKlwfaq9mYCw%26amp%3Bved%3D0CB0Q8gEwAA%26amp%3Bll%3D30.494072%2C-90.41505%26amp%3Bspn%3D0.002233%2C0.003449%26amp%3Bt%3Dh%26amp%3Bz%3D18&hash=46592eef63d53d3b422e8cc0a5f56f565bf5ae08)

* One is proposed to be built at Robert Blvd. and Brown Switch Road in Slidell, La.

There's a roundabout to be installed in the Emory Village, which surrounds Emory University, just northeast of the Atlanta city limits.

Emory Village Roundabout (http://southernroadgeek.blogspot.com/2010/10/emory-village-roundabout.html)


Be well,

Bryant

If we're not being limited to just freeways, CA-1 and CA-19 meet in Long Beach at a roundabout. CA-1 enters from the northwest and exits due east, while CA-19 enters from the due north. Also on this roundabout is a street known as the Los Coyotes Diagonal.

Also roundabouts are quite common in small neighborhoods. In the city of Fillmore, about an hour or two northwest of LA, most of the small streets there have one or two roundabouts.