Skipping the lowest spur

[Alps]

This is coming from the I-335 Des Moines thread - discussion of where Interstate (or US) numbers were skipped and why. Discussion there starts with I-335 and I-710 (CA). I'll add one: In Quebec, there are two A-440s and A-540s. But A-840 and A-940 are unused numbers. Why not put those over in Quebec City instead of duplicating numbers from Montreal? (The Montreal A-440 doesn't even come close to meeting A-440, and may as well be an X25.) Then you also have A-955 without a 755 or 555 and a 973 without a 773.

[Brandon]

Then you have Wisconsin which inexplicably goes straight to I-794 and I-894 skipping everything else lower down.

[JREwing78]

Then you have Wisconsin which inexplicably goes straight to I-794 and I-894 skipping everything else lower down.

Nothing inexplicable about that. You have a lot of I-94 in Wisconsin heading east from Minnesota. It's not inconceivable that Eau Claire or Madison may end up with a I-X94 route at some point.

[Quillz]

I'd imagine it's a combination of future expansion, as well as because some spurs work well when numbered a certain way. (I-580 in CA comes to mind, because it literally connects I-5 to I-80.)

[TheStranger]

If I'm not mistaken, I-580 and I-505 each represent the first ever signed odd x80 and x05 routes in California.  Both were either signed as or planned as I-5W pre-1964 though, so that may explain the digits (and both routes never return to their parents so they are ostensible spurs).

The original 105 was an unsigned segment of US 101/Santa Ana Freeway from 1964-1968 between the San Bernardino Freeway and the East Los Angeles Interchange; I-305 was created in 1982 as an unsigned designation for former I-80 (current US 50/Business 80) between West Sacramento and Route 99 in Sacramento.  

As for I-580...I-180 has never been assigned to a signed road due to the existence of state route 180 in Fresno (and I-180 was only temporarily used for the ex-Route 17 Richmond Bridge freeway before it became part of an I-580 extension).  But I-380 came about in 1968 as a redesignation of then-Route 186, several years after 580 was assigned...

[corco]

I'd imagine it's a combination of future expansion, as well as because some spurs work well when numbered a certain way. (I-580 in CA comes to mind, because it literally connects I-5 to I-80.)

I'm fairly certain that was the rationale for I-705 in Tacoma as well- it was an extension of SR 7 off of I-5.

[Duke87]

I had figured that Quebec avoided numbering autoroutes in the 1xx, 2xx, and 3xx range because they use those numbers for ordinary provincial routes.

In the US, skipping of a lower number is often a sign of a route that was planned but never built. For example, Connecticut has I-291 and I-691 but I-491 never got off the drawing board.

[Brandon]

Then you have Wisconsin which inexplicably goes straight to I-794 and I-894 skipping everything else lower down.

Nothing inexplicable about that. You have a lot of I-94 in Wisconsin heading east from Minnesota. It's not inconceivable that Eau Claire or Madison may end up with a I-X94 route at some point.

Yeah, but you don't have to have a progression of 3dis across the state.  I-894 could come well further west than I-294.

[corco]

Could it be a deference to other states? At least with the even numbers- Minneapolis has 494 and 694 while Chicago has 294. Those cities are all significant to Wisconsinites and near Wisconsin.

I suspect that's the reason Kansas doesn't overlap any interstate numbers with Missouri except where it's the same interstate

[Scott5114]

Could it be a deference to other states? At least with the even numbers- Minneapolis has 494 and 694 while Chicago has 294. Those cities are all significant to Wisconsinites and near Wisconsin.

I suspect that's the reason Kansas doesn't overlap any interstate numbers with Missouri except where it's the same interstate

What about 470?

[corco]

What about 470?

I completely forgot about 470 and that pretty much nixes that theory

[roadfro]

Both of Nevada's spur interstates are 5's: I-515 and I-580. My theory is that it somehow relates to the numbering scheme of Nevada's state routes from the 70s--500s & 600s numbers being assigned to urban state routes, and the routes being obvious spurs.

Nevada's (future) Interstate loop took the first available number: I-215. This freeway went through initial planning much later on, though.

[1995hoo]

I seem to recall reading somewhere that Charlotte's Outerbelt is numbered I-485 in deference to I-285 around Atlanta even though the two cities are about three hours apart (with a third state in between as well). I suppose one could argue that I-485 makes something of a progression since you have the aforementioned I-285, then I-185, I-385, and I-585 in South Carolina. I don't really understand I-985 in Georgia, though. Georgia doesn't seem too concerned with duplication given that there's an I-185 near Columbus, but I guess I-985 is a lot closer to South Carolina's three I-x85s so a duplication there might have  been more of a problem. Still, I-785 was available and was skipped.

Slight threadjack in view of the discussion of duplications being a reason for number selection–my favorite instance of a road number being duplicated is I-68 in Maryland. There is a MD-68 some distance east of there at Clear Spring. When you go through the Clear Spring area heading west on I-70, you see the sign shown at the link below. I roll my eyes every time I see it because to me it underscores how stupid some drivers are.

http://maps.google.com/?ie=UTF8&ll=39.653086,-77.907186&spn=0.024484,0.066047&z=15&layer=c&cbll=39.653113,-77.90743&panoid=t6VZ9lc9ierBLxMPLYF8eA&cbp=12,295.58,,0,8.77

[pianocello]

Does anyone know why the state of Washington skipped some spur route numbers (511, 517, 521, 533, 535, 541, 545, etc.)?

[corco]

Does anyone know why the state of Washington skipped some spur route numbers (511, 517, 521, 533, 535, 541, 545, etc.)?

517 was proposed to be a route but was decommissioned in the 1992 decommissioning before it was ever officially commissioned. Same with 511.

As for the others, I would suspect it follows the possible expansion theory, since those spur numbers usually increase from south to north or west to east. 

[TheStranger]

This thread seems like a good place to note that I-340 has never been used, yet we already have I-540 in Arkansas (future I-49) and in North Carolina!

I'm surprised that when the Baltimore I-170 was canceled, that that number wasn't recycled for what is now I-370 (much as I-880 was reused in California after the Business 80/I-80 switcharound in 1982, showing up in the Bay Area from 1984 onwards).

In Minnesota, the never-built first spur of I-35 (I-335 in Minneapolis) and the first spur of I-94 (I-394 west of Minneapolis) each don't start at 1, but at 3.  For that matter, I-94 does not have any duplicated even-number loop routes!  (Had I-494 been built in Chicago, this wouldn't be the case however.)

[froggie]

In Minnesota, the never-built first spur of I-35 (I-335 in Minneapolis) and the first spur of I-94 (I-394 west of Minneapolis) each don't start at 1, but at 3.

With the exception of MN 62, MnDOT doesn't like route duplication.  I-335 and I-394 were numbered as such because then-MHD (Minnesota Highway Department, precursor to MnDOT) already had a MN 135 and MN 194, which themselves had previously been MN 35 and MN 94 respectively...they were renumbered when the Interstates first came about.

Same reason why the Twin Cities Beltline starts with I-494...MHD already had a MN 294.

[triplemultiplex]

Could it be a deference to other states? At least with the even numbers- Minneapolis has 494 and 694 while Chicago has 294. Those cities are all significant to Wisconsinites and near Wisconsin.

The x94 spurs in Milwaukee were almost certainly chosen to differentiate them from Chicagoland x94's.  If Chicago's taking low number spurs, we're going to start near the top.

This is just a total coincidence, but if there were spurs into Racine and Kenosha; and the airport spur in Milwaukee was an interstate; and if you started numbering these odd spurs at the border and worked your way north, 794 would be 794.
194 - Kenosha
394 - Racine
594 - airport spur
794 - same as reality

It might explain why we'd grab the highest even spur, but only the second highest odd spur for Milwaukee.  Although I get the impression that a 9xx is like an interstate spur of last resort.  So taking that into account, 794 would be the 'better' choice.

[pianocello]

a 9xx is like an interstate spur of last resort.

Except 985...

[deathtopumpkins]

...And 990, and 905, and 980, and (unsigned) 910.

[Quillz]

There's nothing "last resort" about 9xx, it would just logically be the northernmost and easternmost spur assigned, right? As already stated, larger states that have used up 1xx, 3xx, 5xx and 7xx would thus have to make do with 9xx.

Of course, some 3di that should be signed as spurs, like I-476 in Pennsylvania, are not.

[deathtopumpkins]

Not necessarily - not all states number 3dis based on geographic location. Most, to my knowledge anyway, choose a number that has specific meaning, like 580 connecting 5 to 80, or just number them sequentially. For example, VDOT appears to follow this scheme, at least as far as I can tell. There is a 195, a 295, a 495, and an 895 (albeit a state route, this is still an interstate-grade freeway originally planned to carry an interstate 895 shield) (695 probably skipped due to the D.C. 695), as well as a 164 (albeit a state route, this is still an interstate-grade freeway that could carry an interstate 164 shield), 264, 464 (whose proposed number was 364), 564, and 664, and a 381 and 581, with 181 presumably skipped because of Tennessee's.

[jwolfer]

I seem to recall reading somewhere that Charlotte's Outerbelt is numbered I-485 in deference to I-285 around Atlanta even though the two cities are about three hours apart (with a third state in between as well). I suppose one could argue that I-485 makes something of a progression since you have the aforementioned I-285, then I-185, I-385, and I-585 in South Carolina. I don't really understand I-985 in Georgia, though. Georgia doesn't seem too concerned with duplication given that there's an I-185 near Columbus, but I guess I-985 is a lot closer to South Carolina's three I-x85s so a duplication there might have  been more of a problem. Still, I-785 was available and was skipped.

Slight threadjack in view of the discussion of duplications being a reason for number selection–my favorite instance of a road number being duplicated is I-68 in Maryland. There is a MD-68 some distance east of there at Clear Spring. When you go through the Clear Spring area heading west on I-70, you see the sign shown at the link below. I roll my eyes every time I see it because to me it underscores how stupid some drivers are.

http://maps.google.com/?ie=UTF8&ll=39.653086,-77.907186&spn=0.024484,0.066047&z=15&layer=c&cbll=39.653113,-77.90743&panoid=t6VZ9lc9ierBLxMPLYF8eA&cbp=12,295.58,,0,8.77

It seems that GA will defer to other states.  275 is in Tampa/St Pete and then 475 @ Macon and 675 in Atlanta.  It seems that there was some pattern with increasing spur numbers ( ie 295 in Richmond, 495 Washington and 695 in Baltimore) but in the Northeast almost every state has a 195 and 295

[bulldog1979]

Michigan's I-x96s are geographically numbered. I-196 is the westernmost, I-296 is the even downtown bypass for Grand Rapids, I-496 is the even loop for Lansing and I-696 is the even bypass for Detroit.

The I-x75s are also in order, although I-175 was skipped. I-275 is the downtown bypass for Detroit, I-375 is the spur in downtown Detroit, I-475 is next around Flint and I-675 is around Saginaw.

[Revive 755]

Then you have Wisconsin which inexplicably goes straight to I-794 and I-894 skipping everything else lower down.

Nothing inexplicable about that. You have a lot of I-94 in Wisconsin heading east from Minnesota. It's not inconceivable that Eau Claire or Madison may end up with a I-X94 route at some point.

There's also the possibility that Wisconsin didn't want another I-294 or I-494 (I-894 was posted before 1979 right?) that close to the ones in Chicagoland.  As for speculation on I-794, there may have been a desire to extend the designation into Illinois along the cancelled Lake Freeway.  At one time, given the map on Kurumi's site, and the state route numberings, it appears 194, 394, and 594 could have strongly considered for use in Chicagoland.
http://www.kurumi.com/roads/3di/chicago.html

EDIT:  There also may be the skipping of I-164 in Illinois, since I-564 is proposed for the I-64 to new bridge route once the bridge to I-55 east of IL 203 roadway is complete.  I-364 is likely being skipped due to the proximity of MO 364 (which is not MO 164 because supposedly MoDOT thinks 1 is confused with I too much).