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Wednesday, November 24, 2010

'Diverging diamonds' to solve all metro Atlanta's gridlock problems

Posted by Thomas Wheatley on Wed, Nov 24, 2010 at 10:06 AM

After realizing that boring old intersections actually contribute to gridlock, the Georgia Department of Transportation has decided to try some bold new designs sure to make life easier for people driving by themselves to the nearest strip mall.

Among the concepts: roundabouts similar to what motorists will soon encounter near Emory University and the enigmatic diverging diamond, which sounds like the name of a prog rock album.

Here's an example of one of these contraptions, which is planned for Ashford-Dunwoody Road (turn the speakers WAY UP for this video):

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So excited for this to be built! It's about time Georgia be first in something (or one of the first) rather than last. I just hope people's pessimistic outlooks don't ruin it for everyone else!

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Posted by Yay Progress on 11/24/2010 at 10:48 AM

Its billed as a temporary fix (probably for 10 or more years) since it doesn't expand the existing bridge so perhaps not much harm (though I thought that about the Hammond Drive half diamond on 400 until they came in and cleared every tree within a 1/4 mile of the place).

My only concern is 1. there has been no public hearing on the project I guess because the private CID is funding the local match? but I believe public dollars are still being used and it is a public road. 2. How does this design accommodate bus service, Bikes and Pedestrians?

Note to this project would seem to evidence that although there are 4 alternatives billed for "revive 285" this project indicates that they are going to pick a managed lane alternative since under the operational improvement scenario those happen sooner - under the managed lane scenarios Ashford Dunwoody doesn't get rebuilt for a long time....thus the need for this "temp" fix.

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Posted by InAtl on 11/24/2010 at 11:13 AM

You know, as down as I often am on the car-dependency of the areas where these rebuilds are happening, I think it's pretty cool to see GDOT involved in innovative solutions for traffic. Pretty cool. And if the change in traffic patterns forces drivers to be slower and more careful, you've got another positive added.

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Posted by Darin on 11/24/2010 at 11:44 AM

So basically that Muslin Obama is forcing us to create European-style socialist intersections that force people to move "to the left." Disgusting.

Take back our country!

Palin 2012.

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Posted by Andisheh_Nouraee on 11/24/2010 at 11:46 AM

These roundabouts where I see them have always worked well. There are several in South Carolina that I know of that have been there for a decade or so.

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Posted by PistolPete on 11/24/2010 at 12:02 PM

Darin, I agree. While not directly related to this post - well perhaps kind of - The perimeter center really is near a tipping point of being a non car dependent area. The recent downturn in the office market had led to a significant amount of multifamily residential (condos - mid rise and high rise and apartments) being built in the area. So what we have is a good amount of residential, the offices and the retail, even social areas (park place & perimeter point) and several MARTA rail stations.

If they would poke through a couple more streets to provide better connectivity for buses, pedestrians and bikes it would be a giant step. If they would have chosen the BRT or Light Rail alternative that had them running down Hammond Drive it would be transformational.

Admittedly the Hammond Drive widening at 400 and the Johnson Ferry/Abernathy (cobb to perimeter center) widening are opportunities lost.

Anyway, the bridge is a temporary fix so its cool - though there still are pedestrians, bikes and shuttles that use it so hope it accommodates them. But any more permanent "improvements" in the 285 corridor I hope will be with an eye towards the need to ween this area from its heavy car dependence.

Andisheh, wow i have become brainwashed, until you pointed it out I did not realize this plot to move the country to the left. So its true we are sliding in to socialism thanks to our socialist president.

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Posted by InAtl on 11/24/2010 at 12:18 PM

what's wrong with clover leaves and jughandles?

Georgia continues its tradition of having among the best built and maintained roads in the country - and the worst designed.

This will be a catastrophe. People can't drive in this town now.

Oh the accidents you'll witness...

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Posted by harlett o'dowd on 11/24/2010 at 12:45 PM

I'm down with the diamonds but roundabouts ARE a socialist plot, for sure.

The only good idea out of Europe lately is legal hash, and they're starting to fudge on that.

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Posted by oydave on 11/24/2010 at 12:49 PM

I don't see "the perimeter center near a tipping point of being non-car dependent," but it is sure the hell better than anything in the 285/400 corridor. Maybe 15-20 more years (unless our local government makes a concerted effort, which then I think they could do it in 10).

I'm all for a comprehensive and solid streetcar program (if we're going to build one we might as well build a dozen; it can be the ATL's idea of a big city subway system) to connect the MARTA lines to various neighborhoods, bike lanes and pedestrian walkways to keep the ATL densely populated and pedistrian friendly.

And if I never have to get in a car and/or travel outside the perimeter again I couldn't be happier.

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Posted by A girl with a big left foot on 11/24/2010 at 12:54 PM

works in other places, why not here?

we have a highly educated populace who can easily figure out slightly more complex tasks than what they are used to dealing with, right?

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Posted by wesleywhatwhat on 11/24/2010 at 1:12 PM

and someone wants to NEVER travel outside 285 or even get in a car again?

girl, u have to get out more. it's a big world out there.

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Posted by wesleywhatwhat on 11/24/2010 at 1:13 PM

Funny, I never associated our President with fabric (Muslin), and if roundabouts are a socialist plot...then Washington DC is about as socialist as you get...lol

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Posted by scpatl4now on 11/24/2010 at 3:18 PM

As I understand it, pedestrians will cross at the 2 intersections on either side of the bridge (where vehicles go from "right-side" to "left-side"), and walk across in the middle of the bridge. And bikes will ride with traffic - which is exactly what they do now.

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Posted by Yay Progress on 11/24/2010 at 4:04 PM

G w Left Foot - well 15 to 20 years is ok though I would like to push for 10. But many do now take the train to work in the perimeter and walk so I think it could rapidly catch up to midtown or buckhead - guess i'm setting the bar low for non car dependent.

Scpatl4now think you've proved their point - didn't you know Washington DC is where the Socialist in Chief resides? Perhaps only NYC, San Fran and Portland can come close to the number of socialists per square mile.

Yay Progress and it looks like that on the youtube which frankly doesn't sound like a great pedestrian environment since to just cross an intersection on one side of the street you have to cross several movements of traffic ie. north/south And east/west.

Somewhere they've got a map of what's being proposed, unfortunately - getting back to my original post - it hasn't been widely distributed. Suppose if I got by the Perimeter CID office or GDOT office I could take a look at it but why should i have to waste an hour doing that when it could be on the internet.

Also to be clear the CID is doing laudable things and I appreciate their vision for the Perimeter Center: "To create the premier 'walkable' urban center of the Southeast."

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Posted by InAtl on 11/24/2010 at 4:26 PM

btw that flipped diamond looks simple in the youtube, only thing is I think you need to double the number of lanes in all directions for its application on Ashford Dunwoody.

Not saying its not a worthy idea, just that its a little more complicated. Though we did learn how to use the double diamond at the Buckhead loop.

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Posted by InAtl on 11/24/2010 at 4:40 PM

This will do nothing to shorten my personal commute. Therefore, by the reasoning of the masses, it must not be done. Why are MY tax dollars that I WORKED hard for being used to SUBSIDIZE some SOCIALIST intersection that I will never use? If people want a new intersection, add a toll and stop using MY money that I TOILED for? If it doesn't eliminate traffic congestion everywhere or at least on the route of my commute, DO NOT WASTE TAXPAYER DOLLARS THAT WERE STOLEN FROM THE WALLETS OF HARD WORKING SOVEREIGN CITIZENS!

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Posted by Centennian on 11/24/2010 at 7:42 PM

"The perimeter center really is near a tipping point of being a non car dependent area. "

I don't normally do hallucinogenics but thats got to be some good stuff there. Exactly what part of that area is even remotely walkable to anyone but the militant urbanists and those with no other choice.

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Posted by Atlately on 11/24/2010 at 9:04 PM

The bottom line is this...

It doesn't matter how many newfangled or ordinary band-aids the DOT uses the fundamental problems will remain that a) Atlanta is tooooo sprawled and b) there is no real network of roads to disperse traffic. Instead, Atlanta is so cul-de-sac'ed to death that traffic gets concentrated on the few roads that lead to anything.

The only hope for Atlanta is to focus its limited infrastructure dollars in and around its urban job and population centers and connect them by transit. Those that choose to live at the Tennessee line and commute to Alpharetta will just have to fend for themselves.

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Posted by Atlately on 11/24/2010 at 9:16 PM

"I don't normally do hallucinogenics but thats got to be some good stuff there. Exactly what part of that area is even remotely walkable to anyone but the militant urbanists and those with no other choice."

Perimeter Point from the South Terraces Office complex to the Sandy Springs MARTA Station.

Park Place retail with the surrounding residential and office.

The Perimeter Mall via the very well executed landscaped walkway to the Dunwoody MARTA station.

Perimeter Center Parkway's offices to the Dunwoody MARTA station.

A 100 yard walking access from the office complexes on Perimeter Center Parkway near the Dunwoody MARTA Station to Central Parkway where the Cox HQ is simple and would make a walk to those offices and the residential on Peachtree Dunwoody very accessible.

The Med Center MARTA station is connected to the hospitals well and completing the back entrance to Lake Hearn could enable better pedestrian access to the Perimeter Summit complex as well as the old Cox HQ property.

David Southerland of the TMA up there has helped get some bike stuff going on up there.

And there are many people taking the train and private shuttles in the perimeter center, many of whom own cars.

Sure the grid system there is not good, that's what has to be improved as the remaining parcels get built out (along with better pedestrian orientation of new development).

As it stands now there is good transit access and a good mix of live work play with the recent addition of several apartment and condo projects.

Perimeter Center Parkway's LCI has a vision for pedestrian oriented development that could extend the walkable corridor from the Dunwoody MARTA station to Perimeter Point and the Sandy Springs Station. punching the above mentioned connection from Perimeter Center Parkway to Central Parkway/Peachtree Dunwoody could also help.

Its not great but this is a major office/retail center (aka taxbase) for DeKalb and Fulton for which we've made a huge transit investment via the 4 MARTA stations so if we can't improve it in 10 years to where it is not so car dependent then maybe we should just focus on doing car tunnels under the city to improve access for cars to this and other commercial areas along 285.

I do agree that future transit investment decisions should be influenced by implemented or commitments to implementation of zoning and development that supports transit.

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Posted by InAtl on 11/29/2010 at 1:07 PM

@wesleywhatwhat

You misunderstand me. I love to leave the ATL. I especially love going to other places where I can WALK and take mass transit to get from Point A to Point B. What I feel is the worse situation is going to a new city and having to rent a car and DRIVE and fight traffic to see the city. That's what happened the first time I came to Atlanta. Its still happening today. And yes, if I never had to get in a car again (b/c I could rely on accessible and practical mass transit) then I never would. But I have to accept the fact that I live in America, and we love our vehicles.

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Posted by A girl with a big left foot on 11/30/2010 at 4:55 PM

ok.

and yeah, travelling to other cities always makes me wonder why atlanta is so far behind the curve in becoming a walkable city.

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Posted by wesleywhatwhat on 11/30/2010 at 6:05 PM

Part of the reason we are behind the curve is from the Waynes' World effect (that as far as I know we may still be under the same mindset but with different players).

Waynes' World a phrase coined by the AJC back when they did good reporting on this stuff.

Waynes' World a place or state of mind.

Waynes' World goes back to the days of Zell, when Wayne Hill then chair of Gwinnett County dominated the ARC and regional transportation decision making. Wayne Hill's fellow Gwinettians and compatriots included Wayne Shakelford (former head of GDOT - also known as foghorn leghorn) and Wayne Mason - (WM's connections were many but included being brought in as a partner to the Mall of GA which then got the then stalled mall project moving because GDOT then decided to widen the road to the proposed Mall).

Ok yea its much more than that, but still.

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Posted by InAtl on 11/30/2010 at 6:34 PM

"wayne's world effect"?

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Posted by wesleywhatwhat on 12/01/2010 at 8:15 AM

speaking of roundabouts, east atlanta's getting one at flat shoals and mcpherson.

i'm gonna miss taking my life in my hands at that intersection...

http://eaca.net/wp-content/uploads/2010/11…

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Posted by wesleywhatwhat on 12/02/2010 at 2:09 PM
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