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National Boards => General Highway Talk => Traffic Control => Topic started by: jakeroot on April 09, 2015, 01:00:46 PM

Title: What kind of intersection is this?
Post by: jakeroot on April 09, 2015, 01:00:46 PM
Who thinks this is a traffic circle? Perhaps a fancy town-square-style intersection? Maybe just a strange conglomeration of one-way roads with median u-turn points?

I'm holding back from calling it a traffic circle because of the no-turn nature of the top-left/bottom-right ingress legs.

Google Maps Link (http://goo.gl/VzxyMO)

(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FY1gxGRv.png&hash=b30c6bb8274b59fa291e55e7241f12b12f5bc09f)
Title: Re: What kind of intersection is this?
Post by: empirestate on April 09, 2015, 01:42:40 PM
I'd call it a Boston Special.
Title: Re: What kind of intersection is this?
Post by: NE2 on April 09, 2015, 01:49:14 PM
Quote from: jakeroot on April 09, 2015, 01:00:46 PM
I'm holding back from calling it a traffic circle because of the no-turn nature of the top-left/bottom-right ingress legs.
Presumably due to the nearby cross streets. Otherwise it's just like this one in Boston (http://maps.google.com/maps?ll=42.358346,-71.157267&spn=0.005653,0.012392&t=m&z=17).
Title: Re: What kind of intersection is this?
Post by: silverback1065 on April 09, 2015, 04:51:11 PM
A squashed roundabout
Title: Re: What kind of intersection is this?
Post by: jakeroot on April 09, 2015, 04:52:41 PM
Quote from: NE2 on April 09, 2015, 01:49:14 PM
Quote from: jakeroot on April 09, 2015, 01:00:46 PM
I'm holding back from calling it a traffic circle because of the no-turn nature of the top-left/bottom-right ingress legs.

Presumably due to the nearby cross streets. Otherwise it's just like this one in Boston (http://maps.google.com/maps?ll=42.358346,-71.157267&spn=0.005653,0.012392&t=m&z=17).

Very similar indeed. Though most interesting is the difference in age of the intersections. Boston's was built in the 60s, whereas Las Vegas' was built only 5 years ago. Don't get me wrong, I'm sure both have high throughput for traffic, and neither is likely any more dangerous than a normal intersection. It's just that the design is more typical of mid-20th century New England than 21st century Nevada.

Quote from: silverback1065 on April 09, 2015, 04:51:11 PM
A squashed roundabout

That's what I thought. But I'm not sure we can get away with calling it a roundabout of any sort because the movements are signalized.
Title: Re: What kind of intersection is this?
Post by: riiga on April 09, 2015, 05:51:55 PM
Some sort of traffic circle I'd say. It's not a roundabout since it lacks roundabout signage.
Title: Re: What kind of intersection is this?
Post by: kphoger on April 09, 2015, 10:46:25 PM
I would definitely call it a traffic circle, despite the crazy absence of the two slip ramps you mentioned.
Title: Re: What kind of intersection is this?
Post by: roadfro on April 11, 2015, 04:53:55 PM
Some background on this intersection:

This is the intersection of Las Vegas Blvd at Main St & 5th St, in North Las Vegas, NV.

Las Vegas Blvd is old US 91 through the Las Vegas area. At this intersection, it curves from heading due north/south to curving northeast/southwest. Main Street continues to downtown Las Vegas along the northeast/southwest alignment. The north/south part of Las Vegas Blvd is on the old 5th St alignment, and 5th St now begins here.

This intersection used to be just a wide intersection controlled by a set of signals on a old signal bridge/monopole-type setup. North Las Vegas & the RTC has long envisioned developing North 5th Street into a major north/south arterial connecting downtown to developing northern areas (there are few really solid continuous connections presently, and freeway access is out of the way in either direction). The major arterial will eventually be widened all the way to the northern 215 beltway (an interchange and major shopping developments exist there already).

They have been gradually moving forward with this. First, a major widening on 5th took place for the mile or so north of this circle (it was previously as narrow as one lane each direction just north of the circle). This circular intersection was the second stage, and was designed to help improve the flows coming from the new arterial to the north and integrating traffic flowing towards downtown on Main/LVB. The next stage is in progress with construction of a new bridge over I-15 to connect 5th Street at Losee Road.


Quote from: kphoger on April 09, 2015, 10:46:25 PM
I would definitely call it a traffic circle, despite the crazy absence of the two slip ramps you mentioned.

A modified traffic circle is probably the best descriptor using typical traffic engineering lingo.

The absent "slip ramps" (right turns) mentioned are omitted since these are unlikely, given this intersection's proximity to other major roadways that would better facilitate those movements.
Title: Re: What kind of intersection is this?
Post by: jeffandnicole on April 11, 2015, 05:32:16 PM
When I dive down into the GSV, it's hardly any type of circle.  It's really just two intersections with a wide median.  The median has the look of a circle especially from an aerial viewpoint, but there's nothing that indicates it operates like a circle or roundabout. 
Title: Re: What kind of intersection is this?
Post by: vtk on April 11, 2015, 11:17:18 PM
It is a collection of several intersections and one-way roads between them.

On the other hand, a roundabout is exactly that, with a few additional conditions that aren't met here. So calling it a modified traffic circle is also plausibly correct.
Title: Re: What kind of intersection is this?
Post by: RG407 on April 19, 2015, 09:29:33 PM
A traffic oval?  A traffic ellipse?   :spin:
Title: Re: What kind of intersection is this?
Post by: froggie on April 20, 2015, 07:17:48 AM
QuoteIt's not a roundabout since it lacks roundabout signage.

It also has traffic signals.