Is Interstate 95 the only mainline Interstate that still isn't complete?

[Quillz]

It has a fairly long gap that isn't scheduled to be completed until 2014 (at the earliest), but once complete, the original Interstate Highway System, as originally envisioned, should be complete.

Unless there are other gaps in some of the mainline Interstates I'm not aware of. I know that I-70 in Pennsylvania does have a few at-grade junctions, but I don't believe this is considered to be a true gap because it was always designed to route around the at-grade junctions.

[agentsteel53]

70 is a fairly stiff gap.  Is there any plan to build a bypass around Breezewood?

84 in Portland had its last few miles canceled.

Similarly, 70 is not complete through Baltimore - one segment disconnected from the main road was numbered 170 at one point.  I think 83 was also supposed to head further south than it does now.

95 in Boston is pretty hokey as well, being hastily shunted onto the nine-mile ring road in the absence of any other (actually constructed) option.

78 at the Holland Tunnel - was there ever a plan to get rid of the traffic lights on the approach?  If not, why is the route defined to extend past the freeway's end?

86 is not complete in New York, and I do not know if was part of the original 1950s plan.  There is a 1951 video floating around that mentions connecting the Southern Tier cities to the Thruway!  Whether this means that there was to be an 86 segment built as Thruway in the 50s, or if the Thruway was originally intended to take the 86, and not 90 corridor, I do not know.

there is the 73/74 fiasco but I do not know how much of that was planned in the original routing.

[dfilpus]

If you look at urban interstates, the original system will never be complete. I 95 will never run through Washington DC. I 83 will never connect to I 95. I 80 will never connect to the Golden Gate.
I 73/74 is in the same class as I 69, I 49 and I 22. These were all added to the system later. None will be complete in our lifetime.

[WillWeaverRVA]

If you ask Chicago, then I-90 isn't complete either. Of course, we know better.

[shadyjay]

There's a gap in I-93 through Franconia Notch, New Hampshire, but its less-noticeable now...

The "TO I-93" signage has pretty much been replaced and the exits renumbered (from 1-2-3 to 34A-34B-34C), but its definitely not an interstate grade roadway...
Speed Limit posted at 45, sharp curves, no acceleration/deceleration lanes on the exits/ramps, a single lane in each direction, etc. 

[agentsteel53]

I'd forgotten about 93.  81 also has a two-lane segment coming off the Thousand Island Bridge.  Was that ever intended to be four-laned?

[Dougtone]

I'd forgotten about 93.  81 also has a two-lane segment coming off the Thousand Island Bridge.  Was that ever intended to be four-laned?

The Thousand Islands Bridge was never intended to be four-laned, to my knowledge.  To my recollection, traffic volumes don't really warrant that either.

[Alps]

I-86 is not an original part of the I-system.  Neither is I-90 east of I-93 (Ted Williams Tunnel), which confuses me why it was called the "last piece to be built of the original Interstate system."  Not in the least!  I-93, I-81, and I-78 officially cover their "gaps", so they aren't gaps after all.  I am not positive as to whether I-70 officially runs through Breezewood or officially has a break in the middle, in which case any future direct connection would be a true new link in the original system.

[Mergingtraffic]

Correct me if I am wrong but the 95 gap isn't much more than a new interchange and rearranging numbers.  No?  It's not on new allignment or anything.

[mightyace]

^^^

The routing for I-95 once the PTC interchange is built is not the planned routing of I-95.  It was supposed to run from Trenton to the NJ Turnpike near I-287.

What happened and why has been discussed here adnauseum.

[agentsteel53]

I-93, I-81, and I-78 officially cover their "gaps", so they aren't gaps after all. 

certainly, but why was I-78 allowed to be built with traffic lights?  81 I can see because it's so low-traffic it's a vestige of the two-lane-interstate set that was largely phased out by the 80s (I-70 in Utah, I-95 in northern Maine, etc) and 93 is both low-traffic and through a national park, so that kinda makes sense.  But, 78, what gives?  Why define it and then keep it substandard?

[bugo]

What about I-76, I-84, I-86 and I-88?  It could be argued that they are separate Interstates, but it could also be argued that they are gaps.  Depends on how you look at it.

[KEK Inc.]

They should really renumber those...  I still think I-84 should be I-82 and I-82 should be I-7/9/11/13. 

I-86 could be I-x82 (x=odd #) or just US-30. 

I-88 in Illinois should be IL-5 or IL-190 like it used to be...  :\

[Brandon]

If you ask Chicago, then I-90 isn't complete either. Of course, we know better.

So does InDOT, IDOT, and the FHwA. 

[Quillz]

What about I-76, I-84, I-86 and I-88?  It could be argued that they are separate Interstates, but it could also be argued that they are gaps.  Depends on how you look at it.

They are not gaps. AASHTO decided it was better to have two separate Interstates using the same number on opposite ends of the country. Originally, either the western or eastern 76, 84, 86 and 88 was a suffixed route, later renumbered.

[mightyace]

Originally, either the western or eastern 76, 84, 86 and 88 was a suffixed route, later renumbered.

76 is the most interesting in that it was a split interstate before renumbering.  Both parts were I-80S before they became I-76!

[TheStranger]

Originally, either the western or eastern 76, 84, 86 and 88 was a suffixed route, later renumbered.

76 is the most interesting in that it was a split interstate before renumbering.  Both parts were I-80S before they became I-76!

And IIRC, there was a point in time in which we had both the eastern I-76 and the eastern I-80S.

Part of today's eastern I-76/pre-1980 eastern I-80S (the segment through Akron from 71 to today's 80/76 bump) could've been mainline 80 (though I think it was proposed as I-80S) had the western extension to Norwalk been built...

[mightyace]

^^^

I think you're right.

And, IIRC, the current 80/480 routing would have been 80N.  (The turnpike between the ends of the current 480 would have had no I-designation.)

[Alps]

I-88 was never a suffixed Interstate.  The western one was up-designated from a state highway (IL 5), and the eastern one was built after the suffixed Interstates died.

[iwishiwascanadian]

Was I-495 ever signed in New Jersey?  If so wouldn't that constitute as a gap?

[rickmastfan67]

Was I-495 ever signed in New Jersey?  If so wouldn't that constitute as a gap?

It was posted in NJ.
http://www.interstate-guide.com/i-495_nj.html

[SSOWorld]

IL's I-88 was hastily numbered to give that freeway eligibility for 65 mph under the national 55 law exceptions

There are indications of I-495 on the Joe DiMaggio Hwy in NYC (Damn you NYCDOT)

[TheStranger]

IL's I-88 was hastily numbered to give that freeway eligibility for 65 mph under the national 55 law exceptions

Same deal IIRC for I-335 in Kansas

There are indications of I-495 on the Joe DiMaggio Hwy in NYC (Damn you NYCDOT)

Hey, if we can have I-78 and the entirety of Wyoming's I-180 with street-running portions...really, why not have something for 495 between the tunnels?

[iwishiwascanadian]

There are indications of I-495 on the Joe DiMaggio Hwy in NYC (Damn you NYCDOT)

I was just on the West Side Highway (NY 9A) and I believe the signs leading to the Holland Tunnel are shown as To I-495.  I suppose it's talking about the Queens-Midtown Tunnel. 

[Alps]

There are indications of I-495 on the Joe DiMaggio Hwy in NYC (Damn you NYCDOT)

I was just on the West Side Highway (NY 9A) and I believe the signs leading to the Holland Tunnel are shown as To I-495.  I suppose it's talking about the Queens-Midtown Tunnel. 

You mean Lincoln Tunnel.  And what's the Joe DiMaggio Highway anyway?  But no, the signs are indeed pointing I-495 into the Lincoln Tunnel.  Some of them aren't old at all (such as the free-standing shields), but there are a couple of signs in the city that do date to the 1970s or earlier.  I have a few on my NY 495 page .