What are some at-grade intersections in Atlanta in the vast metro area that you all think should be upgraded to grade separated interchanges (or at least semi-interchanges)?
For me I'd start with these:
1.) Windy Hill Rd SE and US 41 in Marietta (SPUI)
2.) SR 54 & SR 74 in Peachtree City (folded diamond or left-turn flyover)
3.) Johnson Ferry Road and Peachtree Dunwoody Road in Dunwoody (diamond)
There are a bunch of them. I cant even hame them all. Especially the outdated interchanges where main arteries meet with interstates in the metro area...I can name a few that need to be converted into DDI's or gutted and completely rebuilt
SR 20 @ IH 85
LaVista Rd @ IH 285
SR 120 (Old Milton Pkwy) @SR 400
There are many others especially in Gwinnett county as the sprawl there continues into Barrow and Walton Counties
SR 20 & I-85 already got an upgrade a couple decades ago when Mall of Georgia was being built. Interesting that the area grew so fast that the interchange is considered outdated now.
IMO SR 20 Should be a minimum of 6 lanes total and 8 lanes total in urban areas in its entire roundabout of the Atlanta suburbs. Especially since no outer perimeter will be built. SR 20 is the closet thing to it...it can take over an hour to get from Buford to Cumming during peak hours on that route
SR 20 in Cumming has serious issues in that Forsyth county is one of the fastest growing in the country since 2010...
I wish Georgia would experiment more with SPUIs when they want to upgrade diamonds instead of DDIs. As far as I know, they only have the one on 400 at Lenox. Also, the way they program their DDIs never seems to improve much. Jimmy Carter and I-85 needs something better than the DDI it has now.
SR 54/74 in Peachtree City desperately needs some sort of upgrade. The US 78/US 278/GA 6 intersection in Lithia Springs also comes to mind.
I have been ad nausem in saying that the DDI'S are a band aid on a bullet wound. I Said that 13 years ago when the one at Ashford Dunwoody DDI was built, the one at Jimmy Carter and the one at Plesant Hill. All 3 of those interchanges needed to be gutted instead of a temporary fix. The only DDI that is half successful is the Windy Hill one over IH 75 and dont quote me on that because Im only in that area during Saturday Braves games. I have not seen it during rush hour...
I hope GDOT and Natalie Dale are catching these posts??? But Shes just an overpaid spokesperson...
Quote from: Tomahawkin on August 14, 2022, 10:50:30 PM
I have been ad nausem in saying that the DDI'S are a band aid on a bullet wound. I Said that 13 years ago when the one at Ashford Dunwoody DDI was built, the one at Jimmy Carter and the one at Plesant Hill. All 3 of those interchanges needed to be gutted instead of a temporary fix. The only DDI that is half successful is the Windy Hill one over IH 75 and dont quote me on that because Im only in that area during Saturday Braves games. I have not seen it during rush hour...
I hope GDOT and Natalie Dale are catching these posts??? But Shes just an overpaid spokesperson...
I know there is a plan to add an access ramp tunnel under Ashford Dunwoody from I-285 to perimeter center that may help some.
https://www.dunwoodyga.gov/government/projects/public-works/perimeter-center-parkway-access-ramp (https://www.dunwoodyga.gov/government/projects/public-works/perimeter-center-parkway-access-ramp)
The whole interchange itself probably needs something creative. My idea would be a partial SPUI but with 2 left turn flyovers from Ashford Dunwoody to I-285.
Quote from: Georgia Guardrail on August 14, 2022, 11:06:08 PMI know there is a plan to add an access ramp tunnel under Ashford Dunwoody from I-285 to perimeter center that may help some.
https://www.dunwoodyga.gov/government/projects/public-works/perimeter-center-parkway-access-ramp (https://www.dunwoodyga.gov/government/projects/public-works/perimeter-center-parkway-access-ramp)
I've never heard of that project before.
Quote from: Georgia GuardrailThe whole interchange itself probably needs something creative. My idea would be a partial SPUI but with 2 left turn flyovers from Ashford Dunwoody to I-285.
I don't think that would fit into the required footprint, especially on the westbound side. Then again, the westbound side is less needed, and GDOT wants to add ramp braids back to Chamblee Dunwoody...
Methinks that this should be discussed in Fictional Highways, because some of these suggestions may never come to pass.
Johnson Ferry Road, Mt. Vernon, and Roswell Road in Sandy Springs, but the chance of that happening is zero.
For decades, US 78 and GA 124 was regarded as the most congested intersection in the state and was supposedly considered for an interchange, but it never happened and the DLT intersection that got built there instead (https://www.google.com/maps/@33.8574806,-84.0201317,247m/data=!3m1!1e3) is surely all that will ever happen.
I'd like to see US 41 upgraded from Hampton to I-75 kinda like what INDOT did in Carmel Indiana
SM-G996U
This is not in the Atlanta area, but the intersection of U.S. 29 and GA 72 in Athens could stand to be upgraded to an interchange. Delays on both routes are getting longer during peak commuting times. Also, turning from U.S. 29 southbound onto GA 72 eastbound is dangerous at night, because the turn is almost 135°, and there's no lighting, and the path of the turn is not marked, so a lot of people mistakenly turn into the westbound lanes if there's nobody waiting in them at the traffic signal.
The entrance to Athens Tech should be included in this as well, since it's just a quarter of a mile south of the intersection with GA 72.
Essentially GDOT needs to look at studies showing what the busiest surface intersections in the state are (assuming they study such things, as I wound assume most DOTs would), and then study grade separations to make them flow more smoothly. At one time, Tennessee's busiest surface intersection was that of US 41/70S/231 and TN 96 in Murfreesboro. That intersection is now a SPUI. It took a while for this to be fully realized, as they first concentrated on improving alternate routes, such as Medical Center Pkwy and building an interchange for TN 99 and I-24, but it was eventually done, and it's a much better situation now.
Quote from: Gnutella on November 23, 2022, 01:36:45 AM
This is not in the Atlanta area, but the intersection of U.S. 29 and GA 72 in Athens could stand to be upgraded to an interchange.
Off topic, but I've long wondered why the connection from that intersection to what's now the Athens Perimeter is there at all. The former route of US 29 had been widened for a mile north of the new freeway and a more-than-minimal interchange built between the two. It would've been cheaper and, IMO, better to leave US 29 there and do away with the ridiculous clusterfrig interchange between new US 29 and the Athens Perimeter.
Quote from: wriddle082 on November 23, 2022, 12:40:50 PM
Essentially GDOT needs to look at studies showing what the busiest surface intersections in the state are (assuming they study such things, as I wound assume most DOTs would), and then study grade separations to make them flow more smoothly. At one time, Tennessee's busiest surface intersection was that of US 41/70S/231 and TN 96 in Murfreesboro. That intersection is now a SPUI. It took a while for this to be fully realized, as they first concentrated on improving alternate routes, such as Medical Center Pkwy and building an interchange for TN 99 and I-24, but it was eventually done, and it's a much better situation now.
One would think that would happen, indeed. Still, I'm amazed at the degree to which people here have come up blank. The first two from the OP are easy to see...
1.) Windy Hill Rd SE and US 41 in Marietta (SPUI)
2.) SR 54 & SR 74 in Peachtree City (folded diamond or left-turn flyover)
...but there aren't many obvious others. For one thing, there could be a rule of "Thou shalt not have an at-grade intersection of two six-lane roads," but I don't think we have a single one.
Quote from: Tom958 on November 24, 2022, 10:00:09 AM
Quote from: Gnutella on November 23, 2022, 01:36:45 AM
This is not in the Atlanta area, but the intersection of U.S. 29 and GA 72 in Athens could stand to be upgraded to an interchange.
Off topic, but I've long wondered why the connection from that intersection to what's now the Athens Perimeter is there at all. The former route of US 29 had been widened for a mile north of the new freeway and a more-than-minimal interchange built between the two. It would've been cheaper and, IMO, better to leave US 29 there and do away with the ridiculous clusterfrig interchange between new US 29 and the Athens Perimeter.
That widening is very recent compared to when new/current US 29 was built. About 15-20 years ago the old US 29 was still just a two or three-lane road.
Another intersection that probably should be an interchange but likely never will be is US 41/Cobb Parkway and Barrett Parkway. Too much development in the immediate vicinity.
Just about every intersection and widening on US 41 over needs to be done in Cobb County! It should be 4 lanes in each direction from Vinings to up past Kennesaw. US 41 is a backup route many use when traffic on IH 75 is FUBAR, which is often especially in the summer when people use it to get to the Battery for Braves games!
Quote from: Tomahawkin on January 07, 2023, 11:22:58 PM
Just about every intersection and widening on US 41 over needs to be done in Cobb County! It should be 4 lanes in each direction from Vinings to up past Kennesaw. US 41 is a backup route many use when traffic on IH 75 is FUBAR, which is often especially in the summer when people use it to get to the Battery for Braves games!
They already have the ROW to make Cobb Parkway 4x4 from I-285 to the South Marietta Loop which would be a great start.
They just have to prioritize actually building it.
Sugarloaf Parkway @ Lawrenceville Highway (US 29) in Gwinnett County. I lived near that intersection for 26 years. It is the intersection from hell!
Yes, Having lived a year off Sugarloaf and Five Forks/Trickum, that intersection is FUBAR. Sugarloaf and Scenic Highway should be 6-8 lanes all throughout Gwinnett, IMO
US 41 all the way from Atlanta Motor Speedway to I-75
SM-G996U
Quote from: RoadWarrior56 on January 11, 2023, 06:23:07 AM
Sugarloaf Parkway @ Lawrenceville Highway (US 29) in Gwinnett County. I lived near that intersection for 26 years. It is the intersection from hell!
Quote from: Tomahawkin on January 11, 2023, 07:36:24 AM
Yes, Having lived a year off Sugarloaf and Five Forks/Trickum, that intersection is FUBAR. Sugarloaf and Scenic Highway should be 6-8 lanes all throughout Gwinnett, IMO
I'm interested in taking a stab at this redesigning this intersection, can someone elaborate on the pressing issues?
Boulevard and Freedom Pkwy!!!
Quote from: jakeroot on January 16, 2023, 08:13:00 PM
Quote from: RoadWarrior56 on January 11, 2023, 06:23:07 AM
Sugarloaf Parkway @ Lawrenceville Highway (US 29) in Gwinnett County. I lived near that intersection for 26 years. It is the intersection from hell!
Quote from: Tomahawkin on January 11, 2023, 07:36:24 AM
Yes, Having lived a year off Sugarloaf and Five Forks/Trickum, that intersection is FUBAR. Sugarloaf and Scenic Highway should be 6-8 lanes all throughout Gwinnett, IMO
I'm interested in taking a stab at this redesigning this intersection, can someone elaborate on the pressing issues?
It's pretty well just capacity. If Sugarloaf was six lanes and had dual left turn lanes at that intersection, it'd likely be enough. The directional split on Sugarloaf is severe, and giving it as much green time as possible creates congestion on US 29, too. The root of the problem is that at the time of construction, Sugarloaf was (and probably still is) classified as a principal arterial with six lanes, a 60 mph design speed, and a 120 foot right-of-way, but doing that would've required total takes of the single-family homes lining one side of what was then two-lane Davis Mill Road between US 29 and Old Norcross Road. Especially in the face of massive cost escalation for road works in the nineties, they crammed four lanes into the existing corridor with minimal ROW acquisition, which is how it remains today.
This intersection is about two miles from my house, where I've lived since 1988, so I've thought about it a lot. It's tempting to imagine an interchange there, but I don't think it'd be a good idea to actually build one. As a matter of fact, at the time that part of Sugarloaf Parkway was built, the plan was to extend Riverside Parkway southward from its current terminus at Old Norcross Road along Monfort Road to Sugarloaf just west of US 29. Even then, AFAIK no interchange was ever proposed there.
I think Tom958 pretty much sums the issues up. And yes, old Davis Mill Road was a very narrow windy two-lane county road that was "repurposed" into Sugarloaf Parkway. There is just too much demand on multiple approaches at certain times of the day, so if you provide more green time to one approach, you make the others even worse. Also, originally Sugarloaf Parkway was never expected to have the kind of traffic volumes on it that it does today. Multiple intersections have had left-turn bays lengthened, etc. To add the icing on the cake at Sugarloaf @ US 29, there is a heavy right-turn movement from EB(SB) Sugarloaf Parkway to SB(WB) US 29. The right-turn lane is very short, presumably due to the existence of underground storage tanks for a preexisting Shell station that sits on that corner. The de-facto right-turn movement is through the pot-holed filled parking lot behind the Shell station, which is mostly empty. On top of everything else, the intersection has a significant skew. I used that intersection on a regular basis between 1996 and 2022. One of the best things of having moved, is that I now do NOT have to figure out how to avoid it at certain hours.
Quote from: Tom958 on January 17, 2023, 06:16:42 AM
Quote from: jakeroot on January 16, 2023, 08:13:00 PM
Quote from: RoadWarrior56 on January 11, 2023, 06:23:07 AM
Sugarloaf Parkway @ Lawrenceville Highway (US 29) in Gwinnett County. I lived near that intersection for 26 years. It is the intersection from hell!
Quote from: Tomahawkin on January 11, 2023, 07:36:24 AM
Yes, Having lived a year off Sugarloaf and Five Forks/Trickum, that intersection is FUBAR. Sugarloaf and Scenic Highway should be 6-8 lanes all throughout Gwinnett, IMO
I'm interested in taking a stab at this redesigning this intersection, can someone elaborate on the pressing issues?
It's pretty well just capacity. If Sugarloaf was six lanes and had dual left turn lanes at that intersection, it'd likely be enough. The directional split on Sugarloaf is severe, and giving it as much green time as possible creates congestion on US 29, too. The root of the problem is that at the time of construction, Sugarloaf was (and probably still is) classified as a principal arterial with six lanes, a 60 mph design speed, and a 120 foot right-of-way, but doing that would've required total takes of the single-family homes lining one side of what was then two-lane Davis Mill Road between US 29 and Old Norcross Road. Especially in the face of massive cost escalation for road works in the nineties, they crammed four lanes into the existing corridor with minimal ROW acquisition, which is how it remains today.
This intersection is about two miles from my house, where I've lived since 1988, so I've thought about it a lot. It's tempting to imagine an interchange there, but I don't think it'd be a good idea to actually build one. As a matter of fact, at the time that part of Sugarloaf Parkway was built, the plan was to extend Riverside Parkway southward from its current terminus at Old Norcross Road along Monfort Road to Sugarloaf just west of US 29. Even then, AFAIK no interchange was ever proposed there.
Quote from: RoadWarrior56 on January 17, 2023, 07:10:13 AM
I think Tom958 pretty much sums the issues up. And yes, old Davis Mill Road was a very narrow windy two-lane county road that was "repurposed" into Sugarloaf Parkway. There is just too much demand on multiple approaches at certain times of the day, so if you provide more green time to one approach, you make the others even worse. Also, originally Sugarloaf Parkway was never expected to have the kind of traffic volumes on it that it does today. Multiple intersections have had left-turn bays lengthened, etc. To add the icing on the cake at Sugarloaf @ US 29, there is a heavy right-turn movement from EB(SB) Sugarloaf Parkway to SB(WB) US 29. The right-turn lane is very short, presumably due to the existence of underground storage tanks for a preexisting Shell station that sits on that corner. The de-facto right-turn movement is through the pot-holed filled parking lot behind the Shell station, which is mostly empty. On top of everything else, the intersection has a significant skew. I used that intersection on a regular basis between 1996 and 2022. One of the best things of having moved, is that I now do NOT have to figure out how to avoid it at certain hours.
Sorry for the delay here. I decided to take a stab at redesigning this whole triangle of roadways. I've posted it over in the "Redesigning Intersections" thread if you want to check it out:
https://www.aaroads.com/forum/index.php?topic=7062.msg2810929#msg2810929
Quote from: jakeroot on January 27, 2023, 12:38:40 AM
Decided to give a go at the Sugarloaf Pkwy / Lawrenceville Hwy intersection triangle in Lawrenceville, GA.
Here is the original location: https://www.google.com/maps/@33.9371798,-84.0299238,825m/data=!3m1!1e3
My comments were inspired by posts in the "Atlanta intersections that should be upgraded to interchanges (https://www.aaroads.com/forum/index.php?topic=32007.msg2806238#msg2806238)" thread.
Just did this one by hand. Not totally to scale. Definitely looking for feedback. This diagram does not show anything but road shapes and general flow, the final design would obviously have plenty of pedestrian and cycle facilities (ideally grade-separated).
(https://live.staticflickr.com/65535/52651758204_1dcffba429_o.png)
LawrencevilleGA Int Redesign V2 (https://flic.kr/p/2odE2my) by Jacob Root (https://www.flickr.com/photos/62537709@N03/), on Flickr
Quote from: jakeroot on January 27, 2023, 12:39:00 AMJust did this one by hand. Not totally to scale. Definitely looking for feedback. This diagram does not show anything but road shapes and general flow, the final design would obviously have plenty of pedestrian and cycle facilities (ideally grade-separated).
(https://live.staticflickr.com/65535/52651758204_1dcffba429_o.png)
LawrencevilleGA Int Redesign V2 (https://flic.kr/p/2odE2my) by Jacob Root (https://www.flickr.com/photos/62537709@N03/), on Flickr
Two weeks later... I said initially that an interchange wasn't necessary, but I guess I could elaborate...
You would've had little way of knowing, but there's a hillcrest on Sugarloaf at the Montfort road connector, and on US 29 there's a substantial gradient uphill from the railroad bridge toward Sugarloaf, as seen in this view (https://goo.gl/maps/vecwKNTiJ1YsE66M8). If there were to be a grade separation at 29 and Sugarloaf, Sugarloaf would need to go over 29, not under. Doing this would require raising and likely razing and replacing Sugarloaf's bridge over the railroad. Of course, the time to have done this would've been during the initial construction. Now, raising the railroad bridge without closing Sugarloaf during construction would require building a new bridge beside the old and pretty much dictating the same thing for the bridge over 29, too. By the time you've done that, you've pretty well obliterated the whole area, so there's no reason to nickel-and-dime the interchange footprint.
Sorry. :-/
Speaking of nickel-and-diming the footprint, why the RTO interchange ramps in your scheme? Why not just draw a couple of SPUIs?
Quote from: Tom958 on February 11, 2023, 12:02:19 PM
You would've had little way of knowing, but there's a hillcrest on Sugarloaf at the Montfort road connector, and on US 29 there's a substantial gradient uphill from the railroad bridge toward Sugarloaf, as seen in this view (https://goo.gl/maps/vecwKNTiJ1YsE66M8). If there were to be a grade separation at 29 and Sugarloaf, Sugarloaf would need to go over 29, not under. Doing this would require raising and likely razing and replacing Sugarloaf's bridge over the railroad. Of course, the time to have done this would've been during the initial construction. Now, raising the railroad bridge without closing Sugarloaf during construction would require building a new bridge beside the old and pretty much dictating the same thing for the bridge over 29, too. By the time you've done that, you've pretty well obliterated the whole area, so there's no reason to nickel-and-dime the interchange footprint.
Sorry. :-/
Speaking of nickel-and-diming the footprint, why the RTO interchange ramps in your scheme? Why not just draw a couple of SPUIs?
No need to apologize, I appreciate the very detailed feedback! This was something I more or less did in an afternoon thinking about how flow could potentially work across the area, so there was certainly not a lot of attention paid to geography. Apart from the rail line...sort of.
Regarding the interchange ramps, I was going for a design that had various movements at each junction, without each junction being redundant with the other. Eg, I didn't see a reason to design left turns from Lawrenceville Hwy to Sugarloaf Pkwy, when Lawrenceville-Suwanee Road could handle that movement. Likewise for the movement from southbound Sugarloaf, using the southern intersection to handle that left turn.
I could have just put SPUIs at each intersection, but like I said, I wanted a design where traffic was distributed across the three major intersections.
Boulevard @ Freedom Pkwy used to be an interchange, when Freedom Pkwy was the I-485 stub. It was converted to an at-grade interchange as part of the Freedom Pkwy compromise. The I-485/Presidential Pkwy/Freedom Pkwy saga has an interesting history that goes back many decades.
I go through that Bleeped up intersection every Thursday for work. I bleeping hate that intersection with a passion. The homeless people there and the MF'ERS on the scooters when it's warm make it annoying and dangerous at the same time. With that in mind all of Ponce is FUBAR in East Atlanta
Add LaVista Rd at 285 to the list. I forgot how bad that interchange is during rush hour. The Bridge needs to be rebuilt. Hopefully that happens in the next 3 years when the 285 toll lanes are built??? The traffic at that interchange gets clogged anytime there is a wreck on 285. Ditto for a lot of surface streets that traverse 285
Quote from: RoadWarrior56 on February 12, 2023, 07:43:06 PM
Boulevard @ Freedom Pkwy used to be an interchange, when Freedom Pkwy was the I-485 stub. It was converted to an at-grade interchange as part of the Freedom Pkwy compromise. The I-485/Presidential Pkwy/Freedom Pkwy saga has an interesting history that goes back many decades.
That's interesting! What kind of interchange was it? Anyone have an old satellite view of this?
Quote from: Georgia Guardrail on February 18, 2023, 06:13:04 PM
Quote from: RoadWarrior56 on February 12, 2023, 07:43:06 PM
Boulevard @ Freedom Pkwy used to be an interchange, when Freedom Pkwy was the I-485 stub. It was converted to an at-grade interchange as part of the Freedom Pkwy compromise. The I-485/Presidential Pkwy/Freedom Pkwy saga has an interesting history that goes back many decades.
That's interesting! What kind of interchange was it? Anyone have an old satellite view of this?
https://www.historicaerials.com/location/33.75929786992031/-84.37016755762872/1981/16
Calling it an interchange was a bit generous. It amounted to commandeering the severed Howell Street for use as slip ramps, plus there was an onramp toward downtown from Boulevard.