Five (or more) way freeway interchanges

[Revive 755]

It appears the Hardy Toll Road extension into downtown Houston, TX will create a five-way interchange with I-10 and US 59.  As mentioned in another thread, there are already a couple stubs for the future ramps:

http://maps.google.com/maps?q=houston,+tx&hl=en&ll=29.768634,-95.345474&spn=0.002782,0.004128&sll=42.032432,-88.091192&sspn=0.215482,0.528374&hnear=Houston,+Harris,+Texas&t=k&z=19

[hm insulators]

Here's another one for the Los Angeles area: The Newhall Interchange is three interchanges in one. First, you have California 14 splitting off from I-5, then just past it, you have I-210 splitting off from the 5. Threaded within this maze is a separate interchange of truck bypass lanes tying in I-5 and the 14. And now Caltrans is building carpool-lane connectors between the 5 and the 14.

And less than two miles to the south of all this, I-405 splits off the 5; there's truck bypass lanes there, too. Some of you might even consider this part of the Newhall Interchange.

[Henry]

I was just trying to design a stack interchange for an imaginary 6-way scenario (3 interstates crossing at a single point, different levels of course) yesterday.

It's a bit of a nightmare. And don't know how many levels one would need for it to be functional.

It's fictional, but it fits the thread's topic.



Remember this is just a quick sketch, nothing to get angry about.

Only access this design doesn't allow is turning to the freeway immediately to the left, but it does allow left turns to the freeway after that (and any other kind of access you'd want).

EDIT: (I could technically could throw in cloverleaf-style loop ramps between the yellow roads, this would permit left turns to the freeways immediately to the left)

Yawwn...

I have been known to create crazy-looking interchanges in my own free time:

http://www.geocities.ws/henryewatson/dreaminterchanges.html

[vtk]

My own design:


This was a good design for its era:

[colinstu]

My own design:
http://vidthekid.info/imghost/cloverstar.png

Beautiful. 100% access, geometric, wouldn't be very tall.

[Alps]

My own design:
http://vidthekid.info/imghost/cloverstar.png

I've played around with that concept - it gets a lot harder for 6, but still doable. I think you can shrink your loops by at least 50% and maybe get the outer ramps concave.

[vtk]

My own design:
http://vidthekid.info/imghost/cloverstar.png

I've played around with that concept - it gets a lot harder for 6, but still doable. I think you can shrink your loops by at least 50% and maybe get the outer ramps concave.

That drawing actually wasn't even meant to be to scale.  Somehow I accidentally didn't make the loops too small.  If interpreted as to-scale, the loops would probably have advisory speeds around 25 to 40 MPH, depending on banking and climate.  And I'd probably have some horizontal and/or vertical clearance issues where the groups of lanes departing the interchange cross over and immediately merge; that needs to happen over a longer distance to work.

Re-doing that with an emphasis on realism would be a fun CAD exercise...

[hbelkins]

I'll take "places that suck" for a thousand, Alex. 

[NE2]

I'll take "places that will suck even more when the freeways are expanded" for a thousand, Alex. 

[hbelkins]

I'll take "places that will suck even more when the freeways are expanded" for a thousand, Alex. 

They say it'll be even easier to get through that certain Place That Sucks once the Bridges Project is finished.

I need to dig out my Facebook post from earlier this week on why I dislike Louisville so much and post it here to give perspective.

[Alps]

I'll take "places that suck" for a thousand, Alex. 

And yet, the elegance of the design - a stack interchange along I-65, except the ramps to the east don't immediately merge back into the mainline. Then you get a nice braided split. It all looks very pretty, it just doesn't function with the volumes pressed into it.

[hbelkins]

I'd never really looked at the intricacies of Spaghetti Junction before this aerial was posted.

The 0 mile marker for I-71 is located at the bridges over the westbound lanes of I-64 at the photo's right. Yet if you look, the I-71 lanes really continue to I-65. The exit from I-64 west to I-65 actually shunts traffic over to the I-71 southbound lanes. And the exit ramps from I-65 to I-64 east/I-71 north funnel traffic onto the I-71 northbound lanes.

Perhaps the exit signage should say "I-71 North, TO I-64 east."

That's a recent photo. I noticed the work ongoing for the ramp up to the Big Four Bridge (the old abandoned railroad bridge to the right of the I-65 bridge) when I went there last week.

[vtk]

The thing was designed in the 60s to accommodate expected traffic through the 80s, right?  It should have been expanded (or torn down and something else built or expanded elsewhere) 20 years ago.  Ignoring the last 30 years of traffic growth, it's a good design.

[hobsini2]

Here is one for sure that has not been mentioned. Jct of La Grange Rd (US 12-20-45), Archer Ave (IL 171), and the Tri State Tollway (I-294) in Justice IL.
http://www.bing.com/maps/print.aspx?mkt=en-us&z=15&s=r&cp=41.746040,-87.847041&poi=Justice%2C%20IL&pp=qyrcrn7pd243&b=1&pt=pb

Other ones I think that could be borderline included are the Mitchell Interchange and the Marquette Interchange(both in Milwaukee) because each of them have side streets that have ramps that are for all tense and purposes involved in them.

Mitchell (I-43/94/894, US 41, Layton Ave):
http://www.bing.com/maps/print.aspx?mkt=en-us&z=16&s=r&cp=42.961627,-87.936639&poi=Milwaukee%2C%20WI&pp=r568467p6zmg&b=1&pt=pb

Marquette (I-43/94/794, US 41, 6th St, Michigan St:
http://www.bing.com/maps/print.aspx?mkt=en-us&z=16&s=r&cp=43.034963,-87.922756&poi=Milwaukee%2C%20WI&pp=r568467p6zmg&b=1&pt=pb

[Henry]

I'll take "places that suck" for a thousand, Alex. 

I'll take "places that will suck even more when the freeways are expanded" for a thousand, Alex. 

They say it'll be even easier to get through that certain Place That Sucks once the Bridges Project is finished.

I need to dig out my Facebook post from earlier this week on why I dislike Louisville so much and post it here to give perspective.

I'd never really looked at the intricacies of Spaghetti Junction before this aerial was posted.

The 0 mile marker for I-71 is located at the bridges over the westbound lanes of I-64 at the photo's right. Yet if you look, the I-71 lanes really continue to I-65. The exit from I-64 west to I-65 actually shunts traffic over to the I-71 southbound lanes. And the exit ramps from I-65 to I-64 east/I-71 north funnel traffic onto the I-71 northbound lanes.

Perhaps the exit signage should say "I-71 North, TO I-64 east."

That's a recent photo. I noticed the work ongoing for the ramp up to the Big Four Bridge (the old abandoned railroad bridge to the right of the I-65 bridge) when I went there last week.

The thing was designed in the 60s to accommodate expected traffic through the 80s, right?  It should have been expanded (or torn down and something else built or expanded elsewhere) 20 years ago.  Ignoring the last 30 years of traffic growth, it's a good design.

Maybe, but that junction became way outdated well before 1980. Hopefully the design that will replace it is a more simplified, freer-flowing one.