What was the original justification for those Maryland spurs-that-aren't-signed-as-spurs?
Internal MD DOT designations? Don't know; Tim handled that, years ago.
I've done a little research:
The I-895 spurs are inventoried as IS
(InterState?) 895-A and 895-B in the MDSHA
Highway Location Reference for
Anne Arundel County.
I don't see an HLR report there for Baltimore city, which would contain I-395-A.
However, all three of these as are contained in various
MDSHA shapefiles, with the same notation:
ID_PREFIX = "IS" (same for the mainline interstates)
ID_RTE_NO = [route number]
MP_SUFFIX = [letter suffix] ("NULL" for mainline routes)
I forgot to mention I-70SprAsh (AKA IS 270-Y) upthread. More on that below...
As far as the Route Log and Finder List goes...
• I-270 = 34.4 mi, comparable to 32.8 + 1.65 (I-270 + I-270SprAsh) = 34.45.
• I-395 = 1.98 mi, comparable to 1.19 + 0.52 (I-395 + I-395Was) = 1.71.
• I-895, well... that's murkier. FHWA says 11.44 mi, and mainline I-895 alone is 14.42 in the HB. It's possible the Route Log and Finder List is showing outdated info
(I've seen other inconsistencies in the past): compare 30.57 mi for
I-695.
Going back to the OP for a second...
I know that Ohio's I-480N isn't officially considered an interstate highway
I'd say that it is one, from the
internal-designation-as-shown-in-shapefiles standpoint, and is equally valid as the MD examples.
ROUTE_TYPE = "IR"
ROUTE_NBR = 00480
TRANS_ID_D = "N"
Maybe I opened up a can of worms here.
Yup! Not your fault, though -- it's that damn can of worms' fault for
existing! 
If we're going to file them under interstates, the Maryland routes are probably a good precedent, if we're including them. I personally think I-480N is probably the best, since it appears that way both on the mile markers and in the Ohio documentation.
I agree. For now at least. I'm still in the process of thinking this whole thing over.
(More below...)Under the system Tim used for Maryland, the route would be I-480SprWar (I-480 Spur Warrensville Heights).
Or not -- as you note below, it could also be a segment of a vanilla (not a spur, that is) I-480, be it with either a letter suffix, or a City Abbreviation.
I don't know that I like that as much.
I'm pretty close to neutral, but leaning slightly toward dislike. I could go with whatever's determined to be the best fit, considering project-wide consistency, Maryland, yadda yadda...
What about the Maryland spurs, then? If we go with the Ohio designation of I-480N, shouldn't we use the internal Maryland designations for consistency, as well (I-395A, I-895A, I-895B)? After all, alternate names allow for files to remain unbroken. There are 32 that include I-395A (as I-395Was), and there are four that have both I-895A and I-895B. I'd be a strong proponent of consistency either way.
Incidentally, and hopefully not going too far off track, the Maryland routes are not even consistent how they're named/listed in usai.csv. For example, why is I-395A not a "spur" but I-895A and I-895B are?
- usai;MD;I-395;;Was;Washington Village, MD;md.i395was;I-395_A
- usai;MD;I-895;Spr;Fer;Ferndale, MD;md.i895sprfer;I-895_SPUR_A,I-895Fer
- usai;MD;I-895;Spr;Fur;Furnace Branch, MD;md.i895sprfur;I-895_SPUR_B
I've wondered that myself in the past.
Can't come up with a 100% satisfactory answer though...It's too bad Tim's disappeared from the Internet; I'd like to be able to ask him his reasoning...
Some background and speculation...
• I-895_SPUR_A and I-895_SPUR_B had been around since the beginning of CHM*, way back before Tim had thought of / formalized a lot of the naming conventions we use today.
•
"I-395A" was added in June 2009. It's possible that at that time, Tim was rethinking his earlier "SPUR" nomenclature, and/or decided this route was better off named as a mainline interstate. As for the earlier routes being listed as SPURs, he was just stuck with that.
Until...•
In July 2012, Tim implemented AltRouteNames, to allow for renaming routes and maintaining compatibility with .list files still using the old deprecated names.
About 50 routes with old-style underscore-suffixes in their names (like US422_E) have had their names updated to our modern style.
At this point, all three routes were updated to modern naming. No more _A, _B, etc. -- routes are now differentiated from the mainline, and one another, by City Abbreviations.
I-395_A -> I-395Was
I-895_SPUR_A -> I-895SprFer
I-895_SPUR_B -> I-895SprFur
No more references to internal designations.
Similarly, in New Jersey: I-95_M -> I-95TreTim had the
opportunity to rename the two I-895 spurs as vanilla I-895 segments with a City abbrev, but for whatever reason, didn't do so.
It could be that based on whatever info he had, he decided the spurs should remain spurs, and that I-395Was was still best considered a vanilla interstate.
(For my part, I can't find any info that would support such a determination)Or it could be that he simply just based the new names off the routes' previous CHM designation.
Adding to the confusion is the I-895Fur AltRouteName for I-895SprFur... my guess here is that it was a short-lived, unintended name, possibly due to Tim leaving out the "Spr" from the Banner column of usai.csv on the first go-round, and then fixing the mistake.
If I may be so bold as to propose changes based on Maryland consistency only (not factoring in the Ohio route decision):
- usai;MD;I-395;Spr;Was;Washington Village, MD;md.i395sprwas;I-395_A,I-395Was
- usai;MD;I-895;Spr;Fer;Ferndale, MD;md.i895sprfer;I-895_SPUR_A,I-895Fer
- usai;MD;I-895;Spr;Fur;Furnace Branch, MD;md.i895sprfur;I-895_SPUR_B,I-895Fur
I-895Fur -- at least as used in this context, as an AltRouteName, would be unnecessary; AltRouteNames are just used to maintain compatibily with .list files using old deprecated route names.
"I-895Fur" isn't in use in any .list files.Right now, I'm kinda leaning the other way -- I could get behind calling these vanilla interstates instead of spurs. Internally, they're all just IS 395-A, IS 895-A, and IS 895-B.
usai;MD;I-395;;Was;Washington Village, MD;md.i395was;I-395_A
usai;MD;I-895;;Fer;Ferndale, MD;md.i895fer;I-895_SPUR_A,I-895SprFer
usai;MD;I-895;;Fur;Furnace Branch, MD;md.i895fur;I-895_SPUR_B,I-895SprFurOf course, I forgot to mention I-270SprAsh in my previous post. This one adds a bit of a wrinkle. It's inventoried as IS 270-Y. Hm. 'Y' often denotes a spur. Even in DOT-speak. That does kind of set it apart from the -A & -B internal suffixes of the other routes. Indeed, this is the one route among this bunch
signed as a SPUR in the field...
I agree. For now at least. I'm still in the process of thinking this whole thing over.
Thought this over as I typed out this post. "For now at least" wins; let me dial back that agreement...
Of course, if we went with the internal designations like I-480N and I-895A, these all change slightly.
I'd discourage this approach.
There's the long-established precedent of moving away from these internal/unsigned designations for .list names. As noted in the MD routes' history above, and similarly I-95_M -> I-95Tre in New Jersey.
Additionally, IMO it'd be best to maintain a good level of distinction between these internal designations, these oddities, from the proper (and I mean
PROPER, like FHWA/AASHTO recognized, and uniformly field-signed) suffixed routes, I-35E, I-35W, I-69E, I-69E, and I-69C.
TL;DR:Thus, may I propose, for the Ohio case:
usai;OH;I-480;;War;Warrensville Heights, OH;oh.i480war;I'll kick the issue of Maryland consistency, and how to handle spurs, not-spurs, and the trickier case of I-270SprAsh, down the road a bit.
