Interstate Highway Question

[Alex]

Are there any other 2-digit Interstates that end at their own 3-digit branch route besides Interstate 64? I-64 does this at both I-264 & 664 in Suffolk, VA.

Thinking more on this I-5 and I-805 almost end at one another, but I-5 continues just a bit further to the border crossing.

As a sidebar, two instances that come to mind of a 2di ending at 3di that is not a numbered branch of itself are I-69 @ I-465 at Indy and I-76 @ I-295 near Camden.

[davewiecking]

I'm going to go out on a limb and theorize that the southern portion of I-95's current ending at I-295 in the middle of nowhere NJ isn't what you have in mind. But I-97's ending at hidden I-595 might count as a sidebar...as would I-70's ending at I-695.

[Mapmikey]

I-45 technically does though may violate the spirit of the question.

I-16 and I-40 come very close but do not...

Mike

[Kacie Jane]

I'm going to go out on a limb and theorize that the southern portion of I-95's current ending at I-295 in the middle of nowhere NJ isn't what you have in mind. But I-97's ending at hidden I-595 might count as a sidebar...as would I-70's ending at I-695.

My hunch is that the "sidebars" would be a tad more common, but still pretty rare.  I-87 ends at I-278 in the Bronx... and aren't both of 97's termini at an x95?

But for the life of me I can't come up with another example of a 2di ending at it's own 3di.

[Rothman]

Not quite on the dot, but I-72 ends shortly after I-172, doesn't it?

[davewiecking]

Shortly after I-172 peels off, but I-72 does continue across the Mississipi River and enters another state before ending. (And yes, both ends of I-97 are at unrelated 3di's.)

[PHLBOS]

I'm going to go out on a limb and theorize that the southern portion of I-95's current ending at I-295 in the middle of nowhere NJ isn't what you have in mind.

That would be a good assumption; especially since that's more of a discontinuity issue (which will finally be resolved in the next few years, see other threads on this matter) rather than an actual terminus.

[Alex]

I-45 technically does though may violate the spirit of the question.

Did not think of the IH 45/345 shared end point in Dallas, thank you Mike! Despite IH 345 being unsigned, I would still count it.

Thinking more on this, had I-179 been signed in Erie as shown on the 1963 rand, another example would be in the system.





Feel free to use this thread for any other random Interstate question.

[SteveG1988]

Formerly, interstate 69 ended at I-465. Interstate 72 on the eastern end just stops at a local road, instead of ending at the interstate. MO is intending to make US36 one day be i-72. Interstate 88 ends at both 294 and 290.

[Alex]

Thinking a little more on this, would another instance of a 2di ending at its 3di branch have have been I-80's west end had both it and I-480 been completed?

[NE2]

Yes, and now FHWA's definition of I-80 ends at the unbuilt connection to I-280.

[Mapmikey]

Another one from the past that has since changed would be I-72 and I-172 at Springfield, IL

Mike

[Grzrd]

I'm going to go out on a limb and theorize that the southern portion of I-95's current ending at I-295 in the middle of nowhere NJ isn't what you have in mind. But I-97's ending at hidden I-595 might count as a sidebar...as would I-70's ending at I-695.

Another sidebar involving suffixed routes instead of 3dis would be, depending on the final alignment selected by TxDOT in Victoria, I-69 terminating at I-69E and/or I-69W, which in turn leads to the interesting situation of I-69C terminating at I-69W and never connecting with its I-69 "parent".

[vdeane]

Honestly, I don't consider suffixed interstates (and most suffixed US routes; probably all except US 9W) to be a parent/child situation.  They function more like the split in the NJ Turnpike than a 3di.  That's one of the reasons I don't like them: none of them are the clear "mainline".

[BakoCondors]

Thinking a little more on this, would another instance of a 2di ending at its 3di branch have have been I-80's west end had both it and I-480 been completed?

This is the first time I've ever seen a map showing 5-W. Thanks for posting 

[Pete from Boston]

Honestly, I don't consider suffixed interstates (and most suffixed US routes; probably all except US 9W) to be a parent/child situation.  They function more like the split in the NJ Turnpike than a 3di.  That's one of the reasons I don't like them: none of them are the clear "mainline".

I never thought of 9W as having a complicated relationship with 9.  Like most folks from west of the Hudson, I hardly consider that the two are related at all.

[vtk]

I'm going to go out on a limb and theorize that the southern portion of I-95's current ending at I-295 in the middle of nowhere NJ isn't what you have in mind. But I-97's ending at hidden I-595 might count as a sidebar...as would I-70's ending at I-695.

Another sidebar involving suffixed routes instead of 3dis would be, depending on the final alignment selected by TxDOT in Victoria, I-69 terminating at I-69E and/or I-69W, which in turn leads to the interesting situation of I-69C terminating at I-69W and never connecting with its I-69 "parent".

As I understand it, I-69W and I-69C will end where I-69 will begin. And I would consider I-69W/C/E to be multiple personalities of the same physical person known as I-69. Or, alternatively, the whole I-69 system is a quantum superposition of different, branchless I-69 routes. Either way, suffixed Interstates aren't children.

[Kacie Jane]

Honestly, I don't consider suffixed interstates (and most suffixed US routes; probably all except US 9W) to be a parent/child situation.  They function more like the split in the NJ Turnpike than a 3di.  That's one of the reasons I don't like them: none of them are the clear "mainline".

I never thought of 9W as having a complicated relationship with 9.  Like most folks from west of the Hudson, I hardly consider that the two are related at all.

9W has both ends at US 9, so the only thing that makes it different from other suffixed routes is that 9 from Fort Lee to Albany isn't called 9E.

6N would be a much better example of an odd duck.

[Pete from Boston]

Honestly, I don't consider suffixed interstates (and most suffixed US routes; probably all except US 9W) to be a parent/child situation.  They function more like the split in the NJ Turnpike than a 3di.  That's one of the reasons I don't like them: none of them are the clear "mainline".

I never thought of 9W as having a complicated relationship with 9.  Like most folks from west of the Hudson, I hardly consider that the two are related at all.

9W has both ends at US 9, so the only thing that makes it different from other suffixed routes is that 9 from Fort Lee to Albany isn't called 9E.

6N would be a much better example of an odd duck.

I guess my point about 9W is that given the isolation brought about by a very large river with few crossings, 9 is barely on the radar for many regular 9W users.  I would assume the reverse is also true.

[jp the roadgeek]

If I-93 is extended down MA 24, it will end at an unrelated 3DI (I-195)

[vdeane]

Honestly, I don't consider suffixed interstates (and most suffixed US routes; probably all except US 9W) to be a parent/child situation.  They function more like the split in the NJ Turnpike than a 3di.  That's one of the reasons I don't like them: none of them are the clear "mainline".

I never thought of 9W as having a complicated relationship with 9.  Like most folks from west of the Hudson, I hardly consider that the two are related at all.

9W has both ends at US 9, so the only thing that makes it different from other suffixed routes is that 9 from Fort Lee to Albany isn't called 9E.

6N would be a much better example of an odd duck.

Well, 9 is the "mainline" as it's not 9E (though it used to be).  The fact that it's in NY also counts, as NY consideres US highways to be NY routes that happen to have a different shield (with the exception of US 2 being inventoried as 2U, I am 100% serious with that comment, and it's not exaggerated at all), and NY uses suffixes for spurs and bypasses.  US 9 and US 9W strike me as being more similar to NY 31 and NY 31A (or NY 5, NY 5A, and NY 5S) than US 11E and US 11W.

[bearcat97]

I-49 ending at I-435 in Kansas City at the Grandview Triangle

[TravelingBethelite]

Another question: was/is there a section of Interstate that doesn't connect to any other? As far as I know, no. This does not include highways that will be as they are constructed. Asking for a friend. 

[vdeane]

Depending on how pedantic you want to get, there's I-587, though I prefer to think of it as connected through the roundabout and Thruway exit 19.

[NE2]

Another question: was/is there a section of Interstate that doesn't connect to any other? As far as I know, no. This does not include highways that will be as they are constructed. Asking for a friend. 

I-585.