Underground grade separations

[roadman65]

List some grade separations between two roadways that happens underground.

South Street underpass and Brooklyn- Battery Tunnel intersect under Battery Park in NYC.

Any more like this?

[pianocello]

Almost all of the interchanges along I-93 in downtown Boston

[Duke87]

Does A-720 in Montreal have any?

If we allow road/rail examples, the Holland Tunnel tubes and the PATH tunnels to Hoboken cross each other. As will the Lincoln Tunnel and the extension of the IRT #7 train when it opens.

[NE2]

Lower Wacker and Lowest Wackest

[1995hoo]

Near the Hilton Stockholm one of the highways enters a tunnel and has an exit that passes in its own separate tunnel underneath the main one in sort of a U-shaped ramp.

[Alps]

Somewhere in the bowels of the Lincoln Tunnel Expressway, there are ramps over ramps under streets. Though mostly not tunneled, it's all below grade. In Philly, US 1/Roosevelt Expwy. ducks under the Broad St. subway - although US 1 is daylit, the subway remains in a tunnel.

[empirestate]

List some grade separations between two roadways that happens underground.

South Street underpass and Brooklyn- Battery Tunnel intersect under Battery Park in NYC.

Any more like this?

By which I assume you mean they *don't* intersect (which is true), hence the topic?

Better not get rail lines involved, or you'll have to spend hours on all of the flying junctions on the NYC subway!

As for multi-level underground road tunnels, I've noticed quite a few while browsing around the major Australian cities.

Are there any cases where there is an underground grade separation, but not in separate tunnels? i.e., you can see the one road from the other as you cross over/under, but they're both still in an underground space?

[NE2]

Are there any cases where there is an underground grade separation, but not in separate tunnels? i.e., you can see the one road from the other as you cross over/under, but they're both still in an underground space?

Not roads, but http://www.nycsubway.org/perl/stations?6:85

[mgk920]

The NB to WB and EB to NB ramps at the rebuilt Mitchell interchange (I-43/94/894) in Milwaukee cross underground.

Mike

[Dr Frankenstein]

Does A-720 in Montreal have any?

One, for University St/Bonaventure Expy/A-10 (Exit 5).

[cpzilliacus]

Near the Hilton Stockholm one of the highways enters a tunnel and has an exit that passes in its own separate tunnel underneath the main one in sort of a U-shaped ramp.

Speaking of Stockholm, Sweden, there's Highway 75, the Southern Link (Södra länken in Swedish), a motorway which is mostly below-grade (including ramps to intersecting surface roads).

[triplemultiplex]

The NB to WB and EB to NB ramps at the rebuilt Mitchell interchange (I-43/94/894) in Milwaukee cross underground.

But the tunnels are not directly on top of one another, so I don't think that counts.

[vtk]

How about underground at-grade intersections?

[Duke87]

Better not get rail lines involved, or you'll have to spend hours on all of the flying junctions on the NYC subway!

It's much easier to list the junctions which are not:

- where the 2 and 3 trains meet on Lenox Ave just south of 145th St (underground)
- where the M and J/Z trains meet at Myrtle Ave and Broadway (elevated)

Every other place in the system where two tracks in regular service cross, they are grade separated.

[Bickendan]

^What about the A line split in Queens?

[NE2]

How about underground at-grade intersections?

Chicago.

[agentsteel53]

How about underground at-grade intersections?

Chicago.

where?  that would be an interesting drive.  clearly I have not scoured Chicago sufficiently, as I have never found one of these.

[empirestate]

http://en.wikipedia.org/wiki/File:Chicago_top_down_view.png

[agentsteel53]

http://en.wikipedia.org/wiki/File:Chicago_top_down_view.png

neato!  I'd never stumbled across that!