I-78 in New York

[TheDon102]

How would the Lower Manhattan Expressway and the other expressways to go along with I-78 affect the traffic situation in and around New York City? Would it have been worth it to construct those expressways?

[thspfc]

When you're posting about something concerning a specific city, state, or region, post in the regional boards below. For New York it would be the Northeast.

[Alps]

How would the Lower Manhattan Expressway and the other expressways to go along with I-78 affect the traffic situation in and around New York City? Would it have been worth it to construct those expressways?

Let's look one at a time.
* LoMEx: Eastbound traffic, right now, is mainly constrained by the Holland Tunnel. The rotary on the NY side is relatively free-flowing, actually. So it would have no effect on EB traffic without adding tubes. Similarly, WB traffic right now is horribly bottlenecked trying to feed into the tunnel. An expressway would just be packed with traffic for a good portion of every day, just like the street grid is now. The only effect LoMEx would have is to ease the congestion on surface streets, but it wouldn't be a very effective freeway to move traffic without additional NJ-side capacity.
* I-478: As originally conceived, this would have headed south to the Manhattan Bridge. Again, there would be no great way to feed it from I-78. Most of the traffic using it now would benefit only marginally by bypassing a couple of signals on the Manhattan side. The I-278 connectivity would presumably be improved on the Brooklyn side, but really only slight advantages to 478 ever being built.
* Williamsburg Bridge: My guess is that there would have been a project at some point to improve or replace the deck so that you wouldn't have 9' lanes on an Interstate. That, in itself, is the greatest benefit here. It would also put more traffic on the Wburg and relieve some congestion on the parallel bridges (Brooklyn, Manhattan, less so Queensboro). Most of this would be Lower Manhattan traffic, since NJ traffic would be so bottlenecked.
* Bushwick Expressway: Sorely needed. For this definition I'm assuming the entirety of unbuilt I-78 from Williamsburg Bridge across to Nassau Expressway / where NY 27 drops down from Conduit Blvd. That is a huge missing link in the NY network and has severely overstressed the only two alternate paths: I-278 -> I-495 -> Grand Central -> I-678, and I-278 -> Belt Pkwy. There is enough independent utility to build that now even without the LoMEx, since as I mentioned above, the LoMEx would just be one big feeder into a bottleneck.
* Nassau Expressway: The JFK Airport area isn't really the existing bottleneck, so adding the WB lanes for Nassau Expwy. and continuing the EB lanes past the airport wouldn't do a whole lot for traffic, but it would be important for the final unbuilt piece:
* Clearview Expressway: Remember how I said I-678 is overstressed? Not only is it handling traffic from the Bushwick, but it's ALSO handling traffic from the Clearview, along with the Cross Island. The southern half of what's now I-295 is another link that really needs to be built right now. With all the money the state and city are pouring into the Van Wyck corridor, they'll still never fix it. The Clearview would help that quite a bit.

To recap:
* Don't bother building expressways in Manhattan.
* Do improve Williamsburg Bridge so it has wider lanes.
* Do build Bushwick -> Nassau -> Clearview.

[TheDon102]

How would the Lower Manhattan Expressway and the other expressways to go along with I-78 affect the traffic situation in and around New York City? Would it have been worth it to construct those expressways?

Let's look one at a time.
* LoMEx: Eastbound traffic, right now, is mainly constrained by the Holland Tunnel. The rotary on the NY side is relatively free-flowing, actually. So it would have no effect on EB traffic without adding tubes. Similarly, WB traffic right now is horribly bottlenecked trying to feed into the tunnel. An expressway would just be packed with traffic for a good portion of every day, just like the street grid is now. The only effect LoMEx would have is to ease the congestion on surface streets, but it wouldn't be a very effective freeway to move traffic without additional NJ-side capacity.
* I-478: As originally conceived, this would have headed south to the Manhattan Bridge. Again, there would be no great way to feed it from I-78. Most of the traffic using it now would benefit only marginally by bypassing a couple of signals on the Manhattan side. The I-278 connectivity would presumably be improved on the Brooklyn side, but really only slight advantages to 478 ever being built.
* Williamsburg Bridge: My guess is that there would have been a project at some point to improve or replace the deck so that you wouldn't have 9' lanes on an Interstate. That, in itself, is the greatest benefit here. It would also put more traffic on the Wburg and relieve some congestion on the parallel bridges (Brooklyn, Manhattan, less so Queensboro). Most of this would be Lower Manhattan traffic, since NJ traffic would be so bottlenecked.
* Bushwick Expressway: Sorely needed. For this definition I'm assuming the entirety of unbuilt I-78 from Williamsburg Bridge across to Nassau Expressway / where NY 27 drops down from Conduit Blvd. That is a huge missing link in the NY network and has severely overstressed the only two alternate paths: I-278 -> I-495 -> Grand Central -> I-678, and I-278 -> Belt Pkwy. There is enough independent utility to build that now even without the LoMEx, since as I mentioned above, the LoMEx would just be one big feeder into a bottleneck.
* Nassau Expressway: The JFK Airport area isn't really the existing bottleneck, so adding the WB lanes for Nassau Expwy. and continuing the EB lanes past the airport wouldn't do a whole lot for traffic, but it would be important for the final unbuilt piece:
* Clearview Expressway: Remember how I said I-678 is overstressed? Not only is it handling traffic from the Bushwick, but it's ALSO handling traffic from the Clearview, along with the Cross Island. The southern half of what's now I-295 is another link that really needs to be built right now. With all the money the state and city are pouring into the Van Wyck corridor, they'll still never fix it. The Clearview would help that quite a bit.

To recap:
* Don't bother building expressways in Manhattan.
* Do improve Williamsburg Bridge so it has wider lanes.
* Do build Bushwick -> Nassau -> Clearview.

Thanks for responding, unfortunately the likelihood of building an expressway's and highways in New York City is around  0.1%.

I also think the bushwick expressway is badly needed, and the clearview is simply a mess mostly due to it not being complete.

[The Ghostbuster]

While I highly doubt this will happen, maybe they should build a tunnel(s) along one of Interstate 78 former alignments as a way of reducing congestion. The Bushwick and the unbuilt portion of the Clearview seem more likely (from a fictional standpoint), than trying to build a Lower Manhattan Tunnel, given all the subway tunnels underneath Manhattan.

[Duke87]

Thanks for responding, unfortunately the likelihood of building an expressway's and highways in New York City is around  0.1%.

Yeah, the practical problem here is that New York City - even the outer boroughs - is an incredibly dense built environment. There is no way to build anything massive across it at surface level without a ton of neighborhood-wrecking eminent domain, something which we've seen the effects of in the past and, quite rightly so, don't want to repeat.

Add to that the massive environmental justice implications (both the Bushwick and the unbuilt Clearview would be passing through minority neighborhoods) and forget it. Especially in New York, where part of the legacy of Robert Moses is a reactionary legal framework designed to make it impossible for the state to ever build anything ever again without 1000% consent from every community it impacts.


In other countries, building these missing freeway links as tunnels in order to minimize any neighborhood disruption might be on the table, and would be a perfectly reasonable idea. But since building anything in New York City requires adding a zero to the end of the price compared to what it would cost in most other developed nations, the ROI is questionable at best and the money isn't there anyway.

[cl94]

Add to that the massive environmental justice implications (both the Bushwick and the unbuilt Clearview would be passing through minority neighborhoods) and forget it. Especially in New York, where part of the legacy of Robert Moses is a reactionary legal framework designed to make it impossible for the state to ever build anything ever again without 1000% consent from every community it impacts.

This is PRECISELY why things take so long to be built in New York and cost more than even other states, let alone other countries. The current laws in New York are designed to prevent anything like what Robert Moses did (planning with 0 outside input) from ever happening again. What that requires, unfortunately, is a very easy challenge process. While the intended purpose was to prevent routing transportation facilities through slums, it has also given NIMBYs more power than in any other state, even if the property impacts are minimal or nonexistent.

TL;DR: blame Robert Moses for screwing it up for the rest of us.

(Personal opinion emphasized)

[Alps]

Thanks for responding, unfortunately the likelihood of building an expressway's and highways in New York City is around  0.1%.

Yeah, the practical problem here is that New York City - even the outer boroughs - is an incredibly dense built environment. There is no way to build anything massive across it at surface level without a ton of neighborhood-wrecking eminent domain, something which we've seen the effects of in the past and, quite rightly so, don't want to repeat.

Add to that the massive environmental justice implications (both the Bushwick and the unbuilt Clearview would be passing through minority neighborhoods) and forget it. Especially in New York, where part of the legacy of Robert Moses is a reactionary legal framework designed to make it impossible for the state to ever build anything ever again without 1000% consent from every community it impacts.


In other countries, building these missing freeway links as tunnels in order to minimize any neighborhood disruption might be on the table, and would be a perfectly reasonable idea. But since building anything in New York City requires adding a zero to the end of the price compared to what it would cost in most other developed nations, the ROI is questionable at best and the money isn't there anyway.

Toll tunnels?

[Duke87]

Toll tunnels?

Presumably would be in any case. But with how expensive it'd be you couldn't pay for it with any reasonable toll amount.

[TheDon102]

Add to that the massive environmental justice implications (both the Bushwick and the unbuilt Clearview would be passing through minority neighborhoods) and forget it. Especially in New York, where part of the legacy of Robert Moses is a reactionary legal framework designed to make it impossible for the state to ever build anything ever again without 1000% consent from every community it impacts.

This is PRECISELY why things take so long to be built in New York and cost more than even other states, let alone other countries. The current laws in New York are designed to prevent anything like what Robert Moses did (planning with 0 outside input) from ever happening again. What that requires, unfortunately, is a very easy challenge process. While the intended purpose was to prevent routing transportation facilities through slums, it has also given NIMBYs more power than in any other state, even if the property impacts are minimal or nonexistent.

TL;DR: blame Robert Moses for screwing it up for the rest of us.

(Personal opinion emphasized)

Robert Moses really destroyed the prospects of building any highway in NYC (even if it provided massive benefits to traffic) after 1960 because of how he handled the Cross Bronx Expressway.

[Alps]

Toll tunnels?

Presumably would be in any case. But with how expensive it'd be you couldn't pay for it with any reasonable toll amount.

I don't know that the idea would be to pay for themselves as much as offset the cost of the tunnels relative to other options.

[cpzilliacus]

Toll tunnels?

Presumably would be in any case. But with how expensive it'd be you couldn't pay for it with any reasonable toll amount.

I don't know that the idea would be to pay for themselves as much as offset the cost of the tunnels relative to other options.

There are tools available now that allow estimates of the cost of traffic congestion to be created pretty easily.

I have sometimes wondered what the cost of east-west congestion across Manhattan are now.  Probably pretty high, which means that the economic demand is there, but that does not mean that the money is there (or could be raised).

[AMLNet49]

Add to that the massive environmental justice implications (both the Bushwick and the unbuilt Clearview would be passing through minority neighborhoods) and forget it. Especially in New York, where part of the legacy of Robert Moses is a reactionary legal framework designed to make it impossible for the state to ever build anything ever again without 1000% consent from every community it impacts.

This is PRECISELY why things take so long to be built in New York and cost more than even other states, let alone other countries. The current laws in New York are designed to prevent anything like what Robert Moses did (planning with 0 outside input) from ever happening again. What that requires, unfortunately, is a very easy challenge process. While the intended purpose was to prevent routing transportation facilities through slums, it has also given NIMBYs more power than in any other state, even if the property impacts are minimal or nonexistent.

TL;DR: blame Robert Moses for screwing it up for the rest of us.

(Personal opinion emphasized)

Robert Moses really destroyed the prospects of building any highway in NYC (even if it provided massive benefits to traffic) after 1960 because of how he handled the Cross Bronx Expressway.

There never were any "prospects" , the only reason there are any freeways in NYC at all is that Moses rammed them through.

Obviously he wanted to build more (real, non stub versions of the LoMEx and MidMEx/Lincoln Tunnel Exp, Bushwick, Nassau and Clearview extensions, Westway, etc) but he still got a ton built, very controversially as we know, compared to what anyone else was willing to do. If it weren't for Robert Moses, there might have been a second I-95 gap, except unlike the one they just filled after 70 years, this one would never get filled because building the Cross Bronx would have been impossible for anyone but Moses

[roadman65]

Add to that the massive environmental justice implications (both the Bushwick and the unbuilt Clearview would be passing through minority neighborhoods) and forget it. Especially in New York, where part of the legacy of Robert Moses is a reactionary legal framework designed to make it impossible for the state to ever build anything ever again without 1000% consent from every community it impacts.

This is PRECISELY why things take so long to be built in New York and cost more than even other states, let alone other countries. The current laws in New York are designed to prevent anything like what Robert Moses did (planning with 0 outside input) from ever happening again. What that requires, unfortunately, is a very easy challenge process. While the intended purpose was to prevent routing transportation facilities through slums, it has also given NIMBYs more power than in any other state, even if the property impacts are minimal or nonexistent.

TL;DR: blame Robert Moses for screwing it up for the rest of us.

(Personal opinion emphasized)

Robert Moses really destroyed the prospects of building any highway in NYC (even if it provided massive benefits to traffic) after 1960 because of how he handled the Cross Bronx Expressway.

There never were any “prospects”, the only reason there are any freeways in NYC at all is that Moses rammed them through.

Obviously he wanted to build more (real, non stub versions of the LoMEx and MidMEx/Lincoln Tunnel Exp, Bushwick, Nassau and Clearview extensions, Westway, etc) but he still got a ton built, very controversially as we know, compared to what anyone else was willing to do. If it weren’t for Robert Moses, there might have been a second I-95 gap, except unlike the one they just filled after 70 years, this one would never get filled because building the Cross Bronx would have been impossible for anyone but Moses

Great point!  Yes we forget to see the good that the one's we dislike have done and have to realize a few things in life.

One, we push for the greatest to hope for the good, meaning you have to ask for more that what you want.  For example if you want a $1 million lawsuit, you ask for $2 million as if you ask for $1 million you may end up with $500K instead.  So asking for $2 million you will get the $ 1 million cause you won't get $2 mill.  Though, I think Moses wanted it all, and not collective bargained for his proposals, in the old Blessing in disguise cliché it is that way.

Two, sometimes the a holes are the ones to get things done.  They may be not likeable people but their effects are long lasting.

Then three, you can only fit so much into a jar without it pouring out.  I live in Florida where we are doing that now to a point we will soon be like NYC, with too much development and established communities from it all, we will be more stuck in moving people across the state.  Heck we got I-4 problems due to greedy developers and a jerk for a former governor (now in the US Senate doing Lord knows what) who gave incentives to build, build, and build more despite what it did to other areas of the nation and the fact our roads do not grow in proportion to the developmental growth.

Other cities should use NY's mistakes as a template, but we all know the story it will never happen.  Development rules out and farming will be a thing of the past until we have no food left.

[sparker]

If the Cross Bronx project had been stopped in its tracks, the chances are that NY metro would resemble Boston and DC, with I-95 deployed over I-287 around the city core.  I-80 would cross the river and end at I-87, and the NJTPK north of I-287 would be unnumbered just like its southern end.  Oh -- and the Sheridan would never have seen the light of day!   And I-278 would continue up the New England Extension to Port Chester, essentially becoming a "Biz 95" corridor.  I for one would have gotten a kick out of the 87/95 reverse multiplex across the Tappan Zee!

What was eventually built was simply due to the timing of Moses' political demise; if it had happened 5-10 years previously, a number of projects would have likely been truncated or plowed under. 

[vdeane]

Or maybe it would have followed I-278 instead.  The current route is about 68 miles (measured from the approximate end of the Somerset Freeway to the CT border); I-278 would be about 73 miles, and I-287 about 88 miles.  Not to mention, the disparity only grows if measured from the exit 10, and part of I-287 wasn't built at the time.

[Interstatefan78]

How would the Lower Manhattan Expressway and the other expressways to go along with I-78 affect the traffic situation in and around New York City? Would it have been worth it to construct those expressways?

Let's look one at a time.
* LoMEx: Eastbound traffic, right now, is mainly constrained by the Holland Tunnel. The rotary on the NY side is relatively free-flowing, actually. So it would have no effect on EB traffic without adding tubes. Similarly, WB traffic right now is horribly bottlenecked trying to feed into the tunnel. An expressway would just be packed with traffic for a good portion of every day, just like the street grid is now. The only effect LoMEx would have is to ease the congestion on surface streets, but it wouldn't be a very effective freeway to move traffic without additional NJ-side capacity.
* I-478: As originally conceived, this would have headed south to the Manhattan Bridge. Again, there would be no great way to feed it from I-78. Most of the traffic using it now would benefit only marginally by bypassing a couple of signals on the Manhattan side. The I-278 connectivity would presumably be improved on the Brooklyn side, but really only slight advantages to 478 ever being built.
* Williamsburg Bridge: My guess is that there would have been a project at some point to improve or replace the deck so that you wouldn't have 9' lanes on an Interstate. That, in itself, is the greatest benefit here. It would also put more traffic on the Wburg and relieve some congestion on the parallel bridges (Brooklyn, Manhattan, less so Queensboro). Most of this would be Lower Manhattan traffic, since NJ traffic would be so bottlenecked.
* Bushwick Expressway: Sorely needed. For this definition I'm assuming the entirety of unbuilt I-78 from Williamsburg Bridge across to Nassau Expressway / where NY 27 drops down from Conduit Blvd. That is a huge missing link in the NY network and has severely overstressed the only two alternate paths: I-278 -> I-495 -> Grand Central -> I-678, and I-278 -> Belt Pkwy. There is enough independent utility to build that now even without the LoMEx, since as I mentioned above, the LoMEx would just be one big feeder into a bottleneck.
* Nassau Expressway: The JFK Airport area isn't really the existing bottleneck, so adding the WB lanes for Nassau Expwy. and continuing the EB lanes past the airport wouldn't do a whole lot for traffic, but it would be important for the final unbuilt piece:
* Clearview Expressway: Remember how I said I-678 is overstressed? Not only is it handling traffic from the Bushwick, but it's ALSO handling traffic from the Clearview, along with the Cross Island. The southern half of what's now I-295 is another link that really needs to be built right now. With all the money the state and city are pouring into the Van Wyck corridor, they'll still never fix it. The Clearview would help that quite a bit.

To recap:
* Don't bother building expressways in Manhattan.
* Do improve Williamsburg Bridge so it has wider lanes.
* Do build Bushwick -> Nassau -> Clearview.

Well said but the Williamsburg Bridge does carry a subway line the J, M & Z trains. I wonder if the expressway construction will affect the subway tracks at the Williamsburg bridge area. Also, the expressway can have a wide median to put the subway tracks there like I-290  Ike & I-90 Kennedy Expressway in Chicago, Illinois

[D-Dey65]

How would the Lower Manhattan Expressway and the other expressways to go along with I-78 affect the traffic situation in and around New York City? Would it have been worth it to construct those expressways?

Let's look one at a time.
* LoMEx: Eastbound traffic, right now, is mainly constrained by the Holland Tunnel. The rotary on the NY side is relatively free-flowing, actually. So it would have no effect on EB traffic without adding tubes. Similarly, WB traffic right now is horribly bottlenecked trying to feed into the tunnel. An expressway would just be packed with traffic for a good portion of every day, just like the street grid is now. The only effect LoMEx would have is to ease the congestion on surface streets, but it wouldn't be a very effective freeway to move traffic without additional NJ-side capacity.
* I-478: As originally conceived, this would have headed south to the Manhattan Bridge. Again, there would be no great way to feed it from I-78. Most of the traffic using it now would benefit only marginally by bypassing a couple of signals on the Manhattan side. The I-278 connectivity would presumably be improved on the Brooklyn side, but really only slight advantages to 478 ever being built.
* Williamsburg Bridge: My guess is that there would have been a project at some point to improve or replace the deck so that you wouldn't have 9' lanes on an Interstate. That, in itself, is the greatest benefit here. It would also put more traffic on the Wburg and relieve some congestion on the parallel bridges (Brooklyn, Manhattan, less so Queensboro). Most of this would be Lower Manhattan traffic, since NJ traffic would be so bottlenecked.
* Bushwick Expressway: Sorely needed. For this definition I'm assuming the entirety of unbuilt I-78 from Williamsburg Bridge across to Nassau Expressway / where NY 27 drops down from Conduit Blvd. That is a huge missing link in the NY network and has severely overstressed the only two alternate paths: I-278 -> I-495 -> Grand Central -> I-678, and I-278 -> Belt Pkwy. There is enough independent utility to build that now even without the LoMEx, since as I mentioned above, the LoMEx would just be one big feeder into a bottleneck.
* Nassau Expressway: The JFK Airport area isn't really the existing bottleneck, so adding the WB lanes for Nassau Expwy. and continuing the EB lanes past the airport wouldn't do a whole lot for traffic, but it would be important for the final unbuilt piece:
* Clearview Expressway: Remember how I said I-678 is overstressed? Not only is it handling traffic from the Bushwick, but it's ALSO handling traffic from the Clearview, along with the Cross Island. The southern half of what's now I-295 is another link that really needs to be built right now. With all the money the state and city are pouring into the Van Wyck corridor, they'll still never fix it. The Clearview would help that quite a bit.

To recap:
* Don't bother building expressways in Manhattan.
* Do improve Williamsburg Bridge so it has wider lanes.
* Do build Bushwick -> Nassau -> Clearview.

Well said but the Williamsburg Bridge does carry a subway line the J, M & Z trains. I wonder if the expressway construction will affect the subway tracks at the Williamsburg bridge area. Also, the expressway can have a wide median to put the subway tracks there like I-290  Ike & I-90 Kennedy Expressway in Chicago, Illinois

There are tunnels where they can be detoured on the Lower East Side, aren't there? If not they would have to have been built before the Williamsburg Bridge was upgraded for I-78.

[BrynM65]

The geography of NYC causes many of the traffic problems given all the corridors eventually have to bottleneck into some form of river crossing.

Add in the fact that to get to and from anywhere in Long Island requires you to traverse already overloaded expressways which again are constrained by river crossing difficulty it makes the whole thing extremely difficult to fix.

I-287 is just way too long way around to be a decent beltway but in money no object fantasy land the Long Island Sound would be bridged so that you had a 3/4 beltway that could pick up interstate non-commuter movements. I expect the NJTP would be furious at losing a huge chunk of potential traffic income if that ever happened though.

Commuting into Manhattan? Yeah it's overdeveloped and the high density is just not designed for cars. 34th and 42nd will be difficult cross streets to use for the long term between the tunnels that I-495 should have connected.

Many comparisons can be drawn with inner London, where people keep trying (and failing) to design things for more cars - the question has to be how to move more people instead. The complete disaster that is the Blackwall Tunnel area (northbound tube opened in 1897, southbound in 1967) is a case in point; the plan is to build a new tunnel that will not connect to roads properly at the northern end meaning the same queues will form as people fight through stop lights to reach the nearest arterial route.

[roadman65]

Well NYC is as good as it will get.  Considering that foot traffic and transit are the main modes for many it won't improve getting more freeways.  Plus development there and sky sprawl is the biggest commodity in that particular city and no one wants now to give up on $$$$.

Plus who knows what the future holds until this whole chaos we live in will take us as sooner or later the bottom will drop and even ancient Rome fell with Caesar and that was one of the greatest super powers throughout written history.  We did succeed them in power and our world is more peaceful then it was centuries ago, but in essence tempers are rising from political arrest here in our nation lately with this Corona Virus and George Floyd murder agrravating many and now they conned some city in this US to disband a city police force because of a few racist cops out there which is like reinstating the 18th Amendment because many drive drunk and get arrested everyday.

Anyway, NYC will not change in that aspect.  Plus we should be pushing more modes of travel in big metros and quit widening freeways to answer problems caused by bad planning because of the open doors on developing because of the get rich demeanor of that aspect for people and corporations.  I am big on getting off the fossil fuel and cleaning our air and less congestion on roads. Yes, NYC has congestion more now than in 1990, but I am for pushing more means even in the biggest metro areas around. 

[Ned Weasel]

Arguable:

This thread should be in Fictional Highways.

Not arguable:

This thread shouldn't go on any further without discussing Paul Rudolph's concept.

https://urbanomnibus.net/2010/10/paul-rudolphs-lower-manhattan-expressway/
https://archpaper.com/2010/11/rudolphs-lomex-in-retrospect/
https://www.curbed.com/2016/5/4/11505214/jane-jacobs-robert-moses-lomex
https://www.archdaily.com/904508/modernist-icon-paul-rudolphs-unbuilt-lomex-completed-in-new-renderings
https://www.designboom.com/architecture/paul-rudolph-unbuilt-proposal-lomex-11-24-2018/
https://www.aaroads.com/forum/index.php?topic=3501.msg77750#msg77750

I'll be brutally honest: Rudolph's concept is so beautiful part of me actually wishes it got built.

[lstone19]

Well said but the Williamsburg Bridge does carry a subway line the J, M & Z trains. I wonder if the expressway construction will affect the subway tracks at the Williamsburg bridge area. Also, the expressway can have a wide median to put the subway tracks there like I-290  Ike & I-90 Kennedy Expressway in Chicago, Illinois

There are tunnels where they can be detoured on the Lower East Side, aren't there? If not they would have to have been built before the Williamsburg Bridge was upgraded for I-78.

No detour available for the Williamsburg Bridge subway line. Trains go across the bridge or they don't cross the East River.

For that matter, even on the Manhattan Bridge, only the lines using the tracks on the south side of the bridge (N and Q) can detour via tunnel. The tracks on the north side (B and D) connect what was formerly the IND on the Manhattan side with what was formerly the BMT on the Brooklyn side and there is no possible detour.