Most over-built interchanges

[flowmotion]

I'm fascinated whenever traffic engineers went overboard. At the peak of their power in the 1950s/60s, they designed and built stuff that turned out to be neither needed or wanted.

My nomination: http://goo.gl/maps/t39j9

US-101 @ Army Street (Cesar Chavez) and Potrero/Bayshore in San Francisco.

What could have been a simple modified diamond between surface streets somehow became a blender. The tight hairpin turns between streets avoid lights but become a twisty maze that the average driver can barely manage.  Not to mention that submerged spaghetti intersections are completely hostile to pedestrians and bicyclists, because the original engineers really didn't care either.

At one point this was configured as a traffic circle. ( http://imgur.com/tL458 ) Probably wasn't that great either, but it looks vastly superior to the final built product.

[Alps]

There are so many ways to make this simpler, and so few reasons to have made this so complicated: https://maps.google.com/?ll=40.895138,-74.252086&spn=0.008386,0.016651&t=h&z=16

[empirestate]

From the not-overly-complex, but perhaps-suspiciously-more-sprawling-than-you'd-think-it-would-need files:

http://goo.gl/maps/a0I1d

and

http://goo.gl/maps/KKUv1

[JREwing78]

I-696 at Mound Rd, Warren, MI
http://goo.gl/maps/piaTI

To be fair, Mound Rd was supposed to have been converted to freeway in this area as M-53 when this interchange was designed and constructed. That obviously never came to pass.

[roadman65]

The I-695 interchange with its parent route North East of Baltimore, MD.  It now serves as a stack interchange where before in its old configuration was not broken as far as I could see.  It always had high speed ramps between the two freeways in all four directions.  True it required the carriageways to switch through the intersection, which is unorthodox in highway design, but not so much to waste millions of dollars to build new flyovers with the same exact characteristics.

[Roadsguy]

They're doing it because of the new HOT lanes they're building on I-95. Way too ridiculously complicated to fit them in on the old design. But it's a real shame, since the old one was much cooler.

[roadman65]

They're doing it because of the new HOT lanes they're building on I-95. Way too ridiculously complicated to fit them in on the old design. But it's a real shame, since the old one was much cooler.

Amen to that!

[Truvelo]

I don't see how anything can be over built. It's much better than being under built where traffic lights and stop lines are built instead of ramps just to save a few $

[kphoger]

I don't see how anything can be over built. It's much better than being under built where traffic lights and stop lines are built instead of ramps just to save a few $

Wow, can I have your extra money, please?

[Alps]

The I-695 interchange with its parent route North East of Baltimore, MD.  It now serves as a stack interchange where before in its old configuration was not broken as far as I could see.  It always had high speed ramps between the two freeways in all four directions.  True it required the carriageways to switch through the intersection, which is unorthodox in highway design, but not so much to waste millions of dollars to build new flyovers with the same exact characteristics.

But it's not overbuilt. It was an unorthodox design, but with the amount of traffic moving through there, the level of construction makes sense.

[NE2]

https://maps.google.com/?ll=55.883026,37.725838&spn=0.005488,0.016512&t=k&z=17
Pretty much every interchange on Moscow's beltway is a cloverleaf. Many have flyovers, but also redundant loops for the same movements. Maybe they're for U-turning traffic.

From the not-overly-complex, but perhaps-suspiciously-more-sprawling-than-you'd-think-it-would-need files:

http://goo.gl/maps/a0I1d

Note that most of the 'waste' here is bridges over swamps. Probably doesn't matter much where they go, so they might as well provide higher-speed connections.

[TheStranger]

I'm fascinated whenever traffic engineers went overboard. At the peak of their power in the 1950s/60s, they designed and built stuff that turned out to be neither needed or wanted.

My nomination: http://goo.gl/maps/t39j9

US-101 @ Army Street (Cesar Chavez) and Potrero/Bayshore in San Francisco.

What could have been a simple modified diamond between surface streets somehow became a blender. The tight hairpin turns between streets avoid lights but become a twisty maze that the average driver can barely manage.  Not to mention that submerged spaghetti intersections are completely hostile to pedestrians and bicyclists, because the original engineers really didn't care either.

At one point this was configured as a traffic circle. ( http://imgur.com/tL458 ) Probably wasn't that great either, but it looks vastly superior to the final built product.

Wasn't this supposed to be the western terminus of the unbuilt Southern Crossing?  I've always surmised that was the reason for the interchange configuration of what is otherwise merely three surface streets meeting up with 101.

[DTComposer]

I'm fascinated whenever traffic engineers went overboard. At the peak of their power in the 1950s/60s, they designed and built stuff that turned out to be neither needed or wanted.

My nomination: http://goo.gl/maps/t39j9

US-101 @ Army Street (Cesar Chavez) and Potrero/Bayshore in San Francisco.

What could have been a simple modified diamond between surface streets somehow became a blender. The tight hairpin turns between streets avoid lights but become a twisty maze that the average driver can barely manage.  Not to mention that submerged spaghetti intersections are completely hostile to pedestrians and bicyclists, because the original engineers really didn't care either.

At one point this was configured as a traffic circle. ( http://imgur.com/tL458 ) Probably wasn't that great either, but it looks vastly superior to the final built product.

Wasn't this supposed to be the western terminus of the unbuilt Southern Crossing?  I've always surmised that was the reason for the interchange configuration of what is otherwise merely three surface streets meeting up with 101.

Correct: http://www.flickr.com/photos/walkingsf/4231803873/sizes/l/

[mcdonaat]

I-10 at LA 1, Port Allen - http://goo.gl/maps/nJd45
This could have been easily solved shifting Interstate-bound traffic to the west and having a more open interchange, the tight spaghetti junction means traffic backs up for MILES to the south for Baton Rouge-bound LA 1 motorists. You have to slow down to 20 MPH, only to merge in with 60 MPH traffic.

I-10 East at Pontchartrain Expressway - http://goo.gl/maps/SviIc
I can't even begin to describe this junction.

[roadman65]

The I-695 interchange with its parent route North East of Baltimore, MD.  It now serves as a stack interchange where before in its old configuration was not broken as far as I could see.  It always had high speed ramps between the two freeways in all four directions.  True it required the carriageways to switch through the intersection, which is unorthodox in highway design, but not so much to waste millions of dollars to build new flyovers with the same exact characteristics.

But it's not overbuilt. It was an unorthodox design, but with the amount of traffic moving through there, the level of construction makes sense.

I do think it might be, as they could have added lanes to the left side exits to speed things up.  However, if HOV is being added it will  be easier for that though. 

One thing they also did was redesign the I-895 interchange to the south that was a directional with Harbor Tunnel being the dominate roadway and I-95 leaving and entering itself to now have I-95 as the main body.  That should have been built the way it is now at first.  I am guessing the HOV had something to do wit that as well? 

[cpzilliacus]

The I-695 interchange with its parent route North East of Baltimore, MD.  It now serves as a stack interchange where before in its old configuration was not broken as far as I could see.  It always had high speed ramps between the two freeways in all four directions.  True it required the carriageways to switch through the intersection, which is unorthodox in highway design, but not so much to waste millions of dollars to build new flyovers with the same exact characteristics.

But it's not overbuilt. It was an unorthodox design, but with the amount of traffic moving through there, the level of construction makes sense.

I do think it might be, as they could have added lanes to the left side exits to speed things up.  However, if HOV is being added it will  be easier for that though. 

One thing they also did was redesign the I-895 interchange to the south that was a directional with Harbor Tunnel being the dominate roadway and I-95 leaving and entering itself to now have I-95 as the main body.  That should have been built the way it is now at first.  I am guessing the HOV had something to do wit that as well? 

I think the change may have been motivated by the I-95 Express Toll Lanes.

But don't forget that I-895 existed for years (back to 1957) as the no-route-number Baltimore Harbor Tunnel Thruway, then "To I-95" before finally getting its own route number in the 1970's or 1980's. 

Before the Fort McHenry Tunnel was completed and opened to traffic in 1985, I-895 was the mainline.

[hbelkins]

There are so many ways to make this simpler, and so few reasons to have made this so complicated: https://maps.google.com/?ll=40.895138,-74.252086&spn=0.008386,0.016651&t=h&z=16

I stayed at that Ramada back during the March 2011 New Jersey meet. That interchange is extremely confusing, and I found it to be poorly signed as well.

[Anthony_JK]

I-10 at LA 1, Port Allen - http://goo.gl/maps/nJd45
This could have been easily solved shifting Interstate-bound traffic to the west and having a more open interchange, the tight spaghetti junction means traffic backs up for MILES to the south for Baton Rouge-bound LA 1 motorists. You have to slow down to 20 MPH, only to merge in with 60 MPH traffic.

The main problem there is the proximity of the Union Pacific rail line that serves the Port of West Baton Rouge, which limited how far you could shift LA 1 westward, as well as maintaining access to the port itself.

I-10 East at Pontchartrain Expressway - http://goo.gl/maps/SviIc
I can't even begin to describe this junction.

Actually, it's a hell of a lot better now, since they rebuilt it in the 1990's to include more direct access between the Ponchatrain Expressway and I-10 (when the Cresent City Connection twin was built). Before then, it really WAS a clusterwhack.

[Federal Route Sixty-Nine]

I nominate Federal Route 175 and IH-20. A four level stack in the fields.

[hbelkins]

Federal Route 175

[NE2]

Hibby has been trolled.

[kphoger]

I-10 at LA 1, Port Allen - http://goo.gl/maps/nJd45
This could have been easily solved shifting Interstate-bound traffic to the west and having a more open interchange, the tight spaghetti junction means traffic backs up for MILES to the south for Baton Rouge-bound LA 1 motorists. You have to slow down to 20 MPH, only to merge in with 60 MPH traffic.

The main problem there is the proximity of the Union Pacific rail line that serves the Port of West Baton Rouge, which limited how far you could shift LA 1 westward, as well as maintaining access to the port itself.

It is possible to move railroads, though I imagine the logistics of making that happen are nowhere near simple, especially for a major line.  The BNSF line was relocated a few years ago when they built the new US-12 super two between Wayzata and Maple Plain, Minnesota.

[J N Winkler]

The I-695 interchange with its parent route northeast of Baltimore, MD.  It now serves as a stack interchange where before in its old configuration was not broken as far as I could see.  It always had high speed ramps between the two freeways in all four directions.  True it required the carriageways to switch through the intersection, which is unorthodox in highway design, but not so much to waste millions of dollars to build new flyovers with the same exact characteristics.

But it's not overbuilt. It was an unorthodox design, but with the amount of traffic moving through there, the level of construction makes sense.

I do think it might be, as they could have added lanes to the left side exits to speed things up.  However, if HOV is being added it will be easier for that though.

I think the change may have been motivated by the I-95 Express Toll Lanes.

The replacement of the I-95/I-695 interchange is indeed part of the Express Toll Lanes construction program.  At the time construction started, it was divided into two phases and MdTA expected to have enough money to start the second phase just as construction was winding up on the first.  But then the ICC intervened and blew a hole through MdTA's finances.  The second phase was recently advertised (and, I believe, awarded), but is five years late and has been radically descoped into an interim improvement until MdTA gets enough money to carry out the full ETL work.

There were several objectives behind the conversion of the I-95/I-695 interchange from a braided interchange into a Maltese cross stack:

*  Increase capacity on I-95 to accommodate expected increases in traffic demand

*  Eliminate left-hand exits and entrances

*  Reduce the sharpness of I-95 mainline curves (in the old braided interchange, these had advisory speeds of 50 MPH)

So, no, I don't think I-95/I-695 is overbuilt.  It may have a significant amount of slack capacity at present, but this has been provided in anticipation of future demand.  Ironically, the true overbuilt interchange is on the other side of Baltimore--I-70/I-695, also another Maltese cross stack, built in anticipation of an I-70 extension into urban Baltimore which was cancelled.

[1995hoo]

They're doing it because of the new HOT lanes they're building on I-95. Way too ridiculously complicated to fit them in on the old design. But it's a real shame, since the old one was much cooler.

Technically those are Express Toll Lanes, not HO/T lanes, because there is no "HOV rides free" provision. All traffic using the lanes must pay at all times.

For those unfamiliar with that interchange, the old setup:



Versus the new setup (with the old "crossover carriageways" still there; this picture is a few years old):



Versus the original plan for the final reconfiguration:

[flowmotion]

My nomination: http://goo.gl/maps/t39j9

US-101 @ Army Street (Cesar Chavez) and Potrero/Bayshore in San Francisco.

Wasn't this supposed to be the western terminus of the unbuilt Southern Crossing?  I've always surmised that was the reason for the interchange configuration of what is otherwise merely three surface streets meeting up with 101.

Correct: http://www.flickr.com/photos/walkingsf/4231803873/sizes/l/

The above link shows a separate intersection north of Army St.

And, if they had built the Southern Crossing connected to the current intersection, it would have been massively under-designed (tight looks that don't handle very much traffic.)