How would Interstate 78 have run through New York City?

[NE2]

One thing I just noticed on the 1958 map: I-95 is shown on the Turnpike. But at that time, it was planned on its own corridor all the way to I-80. Perhaps New York assumed New Jersey would do the logical thing. Or maybe BPR never approved separate I-95 inside I-287, but since New Jersey hadn't requested it (wanting a separate alignment) they couldn't officially add the Turnpike.

Even the map you link to has I-95 on the northern Turnpike.

No it doesn't. https://www.aaroads.com/forum/index.php?topic=14787

[edit]never mind, it has it on both.

[PHLBOS]

One thing I just noticed on the 1958 map: I-95 is shown on the Turnpike. But at that time, it was planned on its own corridor all the way to I-80. Perhaps New York assumed New Jersey would do the logical thing. Or maybe BPR never approved separate I-95 inside I-287, but since New Jersey hadn't requested it (wanting a separate alignment) they couldn't officially add the Turnpike.

Even the map you link to has I-95 on the northern Turnpike.

No it doesn't. https://www.aaroads.com/forum/index.php?topic=14787

Your first link (via NYRoads) does indeed show an I-95 marker/label along the NJ Turnpike just north of the Garden State Parkway interchange (Exit 11).  It's probably shown due to the map showing an alternate/planned routing (via a thin-dotted line) of I-95 showing it connecting to the NJTP around Exit 8A in addition to the other proposed alignment (a separate I-95 running north of I-287).

In hindsight, maybe the more easterly routing should've been pursued.

[D-Dey65]

Yeah, seeing I-495 and NY 495 on the same sign is also pretty surreal.

For me, it's all too familiar.