Interesting article about Interstate Naming Standards; comments even moreso

[Dustin DeWinn]

As title says, the comments here are really interesting - the article is informative too, though you all probably know this

https://ggwash.org/view/73804/decode-the-interstates-what-highway-numbers-actually-mean

[froggie]

Must've been a slow article day at GGW...

(Full disclosure:  I know that article writer personally.  I suspect CP has met him too.)

[LM117]

There are a few very short two-digit interstates that probably should have gotten three-digit numbers instead. North Carolina's aforementioned I-87 is only 13 miles long

Apparently, he's unaware that I-87 will eventually go to Norfolk (or at least the VA state line)...

[Max Rockatansky]

The jab at California's lack of ability to legislatively duplicate route numbers (the I-238 debacle) was a nice touch.

[epzik8]

They must have forgotten that I-99 reaches I-80 in Pennsylvania now.

[PHLBOS]

There are a few very short two-digit interstates that probably should have gotten three-digit numbers instead. North Carolina's aforementioned I-87 is only 13 miles long

Apparently, he's unaware that I-87 will eventually go to Norfolk (or at least the VA state line)...

One of the on-line commenters mentions such as well.

[LM117]

There are a few very short two-digit interstates that probably should have gotten three-digit numbers instead. North Carolina's aforementioned I-87 is only 13 miles long

Apparently, he's unaware that I-87 will eventually go to Norfolk (or at least the VA state line)...

One of the on-line commenters mentions such as well.

One of the responses to that comment claims that NC wanted the I-87 number, which isn't true. NCDOT applied for I-89, but AASHTO changed it to I-87 because they believe that there's a better chance of connecting two I-87's than two I-89's.

https://www.newsobserver.com/news/traffic/article171521622.html

NCDOT had initially requested to call the highway Interstate 89, but there's already one of those, too, in New Hampshire and Vermont. AASHTO spokesman Tony Dorsey said the organization's route numbering committee decided that the new North Carolina highway has a better chance of one day connecting to I-87 in New York than to I-89 in New England, and decided the road between Raleigh and Virginia should be I-87.

[D-Dey65]

This article turned up on my cell phone, but I didn't read it there.

One time one of my brothers asked me about the naming standards for I-495, a.k.a; the Long Island Expressway. I'm surprised nobody brought that up yet. He had just found out about it at the time, but I knew it before I learned to drive. He seemed to suggest it should be I-395, and I told him no, because it was supposed to include the Lincoln Tunnel Thruway, and the never-built Mid-Manhattan Expressway and East Marion-Old Saybrook Bridge.

[KEVIN_224]

I've heard of the cancelled Mid-Manhattan Expressway...but Lincoln Tunnel Thruway?

[D-Dey65]

I've heard of the cancelled Mid-Manhattan Expressway...but Lincoln Tunnel Thruway?

Whatever they call NJ 495 now.

[Dustin DeWinn]

This article turned up on my cell phone, but I didn't read it there.

One time one of my brothers asked me about the naming standards for I-495, a.k.a; the Long Island Expressway. I'm surprised nobody brought that up yet. He had just found out about it at the time, but I knew it before I learned to drive. He seemed to suggest it should be I-395, and I told him no, because it was supposed to include the Lincoln Tunnel Thruway, and the never-built Mid-Manhattan Expressway and East Marion-Old Saybrook Bridge.

I was wondering that myself, actually. I grew up in Long Island and now live in NC and there's a 495 there too. We're they supposed to connect?

[vdeane]

3dis are allowed to duplicate in different states.  2dis aren't supposed to, but try telling that to I-76/I-84/I-86/I-87/I-88.

[sparker]

3dis are allowed to duplicate in different states.  2dis aren't supposed to, but try telling that to I-76/I-84/I-86/I-87/I-88.

2di duplications began being allowed circa 1976, when it was decided to eliminate suffixed routes -- and all the even designations between and including 70 to 90 were already deployed.  So by 1981 the western I-80N became a second I-84, CO & NE's I-80S became I-76 (CODOT actually requested that number, since it tied in with their 1976 centennial); ironically both iterations of I-76 were originally intended to be designated I-80S!  The shortest I-80 suffix, I-80N in IA, became an extension of the I-680 Omaha bypass.  And in the oddest of all these, the E-W I-15W in ID became the (then) western I-86 (and between 1984 and 1999 the only I-86 iteration).  And the western I-88 apparently got its number from its designation year (1988, of course); most observers posit I-82 as a more appropriate number considering its proximity to I-80.  But the common factor here was that there were no other numbers available for these routes (unless one likes ultra-long 3di's) without going way out of grid bounds -- hence the duplications.  And then there's I-87 -- which because of NCDOT's lapse of judgment compounded by AASHTO/SCOURN's lack of due diligence got its misbegotten number (it should by rights have a heretofore unused even number between 40 and 64).  I guess we posters just may be the only ones who give a shit about these things; agencies as of late have tended to view such matters with a collective shrug of the shoulders.   

[vdeane]

Of the duplications, the only one I can't figure out how to avoid is I-76.  Western I-84 could have become I-82 (with existing I-82 becoming I-7 or I-9), and western I-86 should be a 3di.  Western I-88 could have been avoided if NMSL hadn't happened (it was only designated so it could have a speed limit of 65).

I don't recall there being an official rule change on duplicating 2dis, just the officials being either less willing to and/or less able to monkey with the grid to keep things neat and tidy as roadgeeks would.

[Mapmikey]

Of the duplications, the only one I can't figure out how to avoid is I-76.  Western I-84 could have become I-82 (with existing I-82 becoming I-7 or I-9), and western I-86 should be a 3di.  Western I-88 could have been avoided if NMSL hadn't happened (it was only designated so it could have a speed limit of 65).

Slightly ridiculous but would work:  Change I-70 at Columbus to follow I-71 northeast then replace all of I-76;  I-70 from Columbus to Washington PA becomes extended I-68; I-70 from Washington to New Stanton can be a 3di (or removed from interstate system); Breezewood to Hancock can become an extended I-99; Hancock to Baltimore can be more I-68

Even MORE ridiculous:  Renumber western I-76 as part of I-70; renumber Denver to Baltimore as I-64; renumber I-64 as I-62

[sparker]

Of the duplications, the only one I can't figure out how to avoid is I-76.  Western I-84 could have become I-82 (with existing I-82 becoming I-7 or I-9), and western I-86 should be a 3di.  Western I-88 could have been avoided if NMSL hadn't happened (it was only designated so it could have a speed limit of 65).

I don't recall there being an official rule change on duplicating 2dis, just the officials being either less willing to and/or less able to monkey with the grid to keep things neat and tidy as roadgeeks would.

Since E-W Interstate numbers ending in "4" seem, at least historically, to denote longer-distance and/or regionally vital corridors (e.g. 44, 64, 94), the 3 states the old I-80N traversed probably got together and requested I-84 for the designation.  Curiously, some of the first signage iterations (before the current I-82 alignment in OR & WA was added to the system) showed it as I-82 -- before Portland pissed & moaned about not being on a "major" interstate (IMO a concept oversold at the network's inception -- and ironically well before that city's subsequent opposition to new-terrain freeways) which led to the original suffixed number.  But I-82 definitely would have worked; the OR/WA connector, if the decision was to retain an even number there, could have become an early I-86 or 88. 

[sprjus4]

Since E-W Interstate numbers ending in "4" seem, at least historically, to denote longer-distance and/or regionally vital corridors (e.g. 44, 64, 94)

I-14 TX-GA, I-74 IA-SC

[wanderer2575]

Since E-W Interstate numbers ending in "4" seem, at least historically, to denote longer-distance and/or regionally vital corridors (e.g. 44, 64, 94)

I-14 TX-GA, I-74 IA-NC

I-4   

[vdeane]

Of the duplications, the only one I can't figure out how to avoid is I-76.  Western I-84 could have become I-82 (with existing I-82 becoming I-7 or I-9), and western I-86 should be a 3di.  Western I-88 could have been avoided if NMSL hadn't happened (it was only designated so it could have a speed limit of 65).

I don't recall there being an official rule change on duplicating 2dis, just the officials being either less willing to and/or less able to monkey with the grid to keep things neat and tidy as roadgeeks would.

Since E-W Interstate numbers ending in "4" seem, at least historically, to denote longer-distance and/or regionally vital corridors (e.g. 44, 64, 94), the 3 states the old I-80N traversed probably got together and requested I-84 for the designation.  Curiously, some of the first signage iterations (before the current I-82 alignment in OR & WA was added to the system) showed it as I-82 -- before Portland pissed & moaned about not being on a "major" interstate (IMO a concept oversold at the network's inception -- and ironically well before that city's subsequent opposition to new-terrain freeways) which led to the original suffixed number.  But I-82 definitely would have worked; the OR/WA connector, if the decision was to retain an even number there, could have become an early I-86 or 88. 

I'm pretty sure that's a coincidence.  The only number significance for 2dis beyond odd/even is that x0 and x5 numbers are supposed to be "transcontinental".

[dlsterner]

Since E-W Interstate numbers ending in "4" seem, at least historically, to denote longer-distance and/or regionally vital corridors (e.g. 44, 64, 94)

I-14 TX-GA, I-74 IA-NC

I-4   

Although I-4 isn't really "longer distance", it could be argued that it still is "regionally vital".  That said, I suspect that the 2di's ending with "4" being more major is merely coincidental.

[GaryV]

Since E-W Interstate numbers ending in "4" seem, at least historically, to denote longer-distance and/or regionally vital corridors (e.g. 44, 64, 94)

I-14 TX-GA, I-74 IA-NC

I-4   

Although I-4 isn't really "longer distance", it could be argued that it still is "regionally vital".  That said, I suspect that the 2di's ending with "4" being more major is merely coincidental.

Probably slightly more than coincidental, but not a planned standard.

X4 being roughly mid-way between one X0 and the next X0, it is logical that in some cases there would be a "fill in the blank" route of some distance between the 2 zero-routes.  More likely than X2 or X8, as these would be near to their zero-route and likely wouldn't need to be as long.  X6 might equally have been selected as the  "fill-in" number; it just seems like X4 was chosen more often.  We also need to remember that several routes are later additions to the system, replacing the bannered routes; it's logical that those routes thought of as "deserving" a X0-N or -S banner would be longer on average.

X1 or X9 would have served the same purpose for N-S routes, and that seems to have happened in several cases as well (e.g. 29, 59, 81).  But again, not a rule, merely a logical pattern.

[Rover_0]

The only unwritten convention that I seem to notice is that x2 or x7 Routes tend to be shorter (<300 miles) and/or intrastate routes, such as I-2, I-12, I-17, I-27, I-37, Future I-42, I-72, I-82, I-87 (S), and I-97. Of course, there are long x2/x7 exceptions, like I-57 and I-77, and short non x2/x7 Interstates, like I-19, I-41, and I-86 (W), but it's interesting to see how many of the x2/x7 routes seem to follow this method.

[1995hoo]

The only unwritten convention that I seem to notice is that x2 or x7 Routes tend to be shorter (<300 miles) and/or intrastate routes, such as I-2, I-12, I-17, I-27, I-37, Future I-42, I-72, I-82, I-87 (S), and I-97. Of course, there are long x2/x7 exceptions, like I-57 and I-77, and short non x2/x7 Interstates, like I-19, I-41, and I-86 (W), but it's interesting to see how many of the x2/x7 routes seem to follow this method.

The real I-87 fits that list because the entire route is within New York State.

[Duke87]

This article turned up on my cell phone, but I didn't read it there.

One time one of my brothers asked me about the naming standards for I-495, a.k.a; the Long Island Expressway. I'm surprised nobody brought that up yet. He had just found out about it at the time, but I knew it before I learned to drive. He seemed to suggest it should be I-395, and I told him no, because it was supposed to include the Lincoln Tunnel Thruway, and the never-built Mid-Manhattan Expressway and East Marion-Old Saybrook Bridge.

So, it's a common misnomer that the LIE gets its first digit even 3di number because a planned LI Sound crossing was intended to connect it back to I-95 at the east end.

In actuality, I-495 as originally designated ended at the interchange with the Clearview (at the time designated I-78), which qualified for first digit even since both ends were at another interstate. The entire rest of the LIE east of there was designated, and signed as, NY 495. As seen in this 1965 photo:


Subsequently, the rest of the road was added to the interstate system, and this was done by extending I-495 rather than changing the number for simplicity's sake. Thus creating the nonconformance with convention that currently exists.

[sprjus4]

The original I-87 fits that list because the entire route is within New York State.

FTFY. The NC-VA I-87 is newer than the NY I-87, but both are very much real interstate highways.