It seems like there are many occasions where 3-digit interstates are numbered a bit strangely. The DOTs (or whatever agency is responsible for selecting highway numbers) have made some strange choices. For the 3-digit interstate highways, either four digits (2, 4, 6, or 8 - in the case of loops) or five digits (1, 3, 5, 7, or 9 - in the case of spurs) are available. There are many occasions where I higher digit was selected when lower digits are available.
Here are a few examples I've noticed:
I-375 in Detroit, MI - why not I-175?
I-516 in Savannah, GA - why not I-116?
I-675 outside Atlanta, GA - why not I-475?
I-794 in Milwaukee, WI - why not I-594?
I-459 in Birmingham, AL - why not I-259?
I-520 in Augusta, GA - why not I-120?
I-820 in Fort Worth, TX - why not I-620?
I-530 in Arkansas - why not I-130?
I-684 in New York and Connecticut - why not I-284?
I-691 in Connecticut - why not I-491?
These are just some examples of what I'm talking about. I don't know why this bothers me, but it just does. LOL
For the I-675, there is a I-475 that bypasses Macon, GA. But there is no I-275 in Georgia.
I believe these are at higher mile markers so the lower numbers were bypassed in case of another 3DI was built/commissioned at a lower mile marker of the 2DI.
Wasn't the idea in Texas that the loop numbers would increase as you move east across the state? So, Midland/Odessa, Abilene, and one other city would have those lower numbers if ever built. I'm not sure where I heard that so I could be full of baloney.
But that's why San Antonio is I-410 and Houston is I-610, I think, so that El Paso could have I-210 if ever necessary.
In NC, the state has a plan for future Interstates all over the state, which had numbers assigned to proposed routes. Now some of those Interstates are being created, the original numbers are being used. That is why, when US-117 was converted to an Interstate, it got the number I-795. All of the lower odd numbers have been reserved for other future Interstate spurs off of I-95. I-195 was renumbered to I-295. If I recall correctly, I-395 and I-595 were reserved for US-64 and US-264, east of I-95. Greensboro has two future interstates that are now signed "Future" as I-840 and I-785. These numbers go back to the original plan.
Virginia seems to just not want to disrupt its numbering system anymore. The last Virginia state route renumbered for a 3di was VA 195 (now 186) in the 1970s. Since then I-564 was created with VA 164 and 364 already extant. I-785 will just be an extension of NC's, and the proposed I-895 (now VA 895) was chosen over 695 because Chesterfield County didn't have an SR 895 but does 695.
CA uses some numbers which are reminiscent of the former ones. CA-11 become I-110, which happened to be the lowest available number. but CA-7 became I-710 instead of I-310 just for easier driver recognition.
CT uses its only 3di on I-95, (395), just in case they renumber anything south of New Haven. Like US7, if that pipe dream ever is built.
I'm willing to bet a fair number of these are due to canceled freeways too, like with CT I-691. 291 already exists, and 491 was planned: http://www.kurumi.com/roads/ct/i491.html
Same goes for NY/CT I-684. 284 (http://en.wikipedia.org/wiki/Interstate_284) and 484 (http://www.kurumi.com/roads/ct/i484.html) were planned, both in CT.
Another California thought:
Renumbering is something that CalTrans wants to avoid as much as possible - which isn't always a good thing, as it allows unbuilt routes to hog smaller-digit numbers, and prioritizes even the shortest existing corridors over newer (and possibly more important) routes.
Cases in point:
- The usage of future Interstate 905 for what was once state route 117 (and before that, an extension of route 75) in San Ysidro - 705 was and remains available, and 305 only exists as a FHWA paper designation and isn't in use as a signed route.
- The creation of Interstate 238 occurred while former Interstate 480 was already a short state route in SF that could have easily been renumbered to another designation. Moving 3di designations within a metro area isn't unprecedented (it has happened in NYC in the past)
- The I-580 extension along former Route 17 specifically exists because CalTrans did not want to renumber the Central Valley state route 180 to accommodate the originally chosen designation of I-180. (Going to the 1964 renumbering, state routes 5, 8, 15 all got nixed to accommodate interstates, and what had been state route 10 was renumbered in the late 1950s for that reason as well - yet 180 was retained then!)
- While the same thoughts behind today's I-110 and I-710 likely were in play for today's 580 and 505 (which were both originally part of the pre-1964 Interstate 5W), wouldn't assigning 105 and 180 have made sense then? I-5 at the time had no odd 3dis, with unsigned 105 being given to the southernmost tip of US 101 briefly in 1964 (only to then be moved to today's Century Freeway in 1968)...and the only pre-1964 I-80 branch routes were the even-first-digit 280, 480, 680.
Washington State has just three 3dis - I-205 (whose southern end is in Oregon), I-405 around the east side of Seattle, and I-705 in Tacoma. Why no I-105?
The argument that there's no 705 in Oregon would make sense, seeing there is I-105 in Eugene, and I-205 serves both states, but there are duplicative 405s so that Seattle's 405 should really be I-605...and Tacoma's I-705 could be I-305 or I-505.
In Oregon, I-305 was originally planned for Salem (cancelled, later became Oregon 72/Business Route 99E, Salem Parkway) and I-505 was originally planned for N.W. Portland (cancelled, stub ramp became off-ramp for U.S. 30 and Yeon Boulevard). So that provides some logic to 705's numbering - but that logic is still defeated by the two 405s. And Oregon/Washington don't agree with route numberings anyways - in the eastern part of the state, state route numbers always change at the state line (Oregon 3 and 11 become SR 129 and SR 125).
This would explain a lot. I never thought of it, but there is a pattern of the way the first numbers are selected as I can see in New York for I-90 spurs going from 1 to 8 from West to East, and then I-990 was added later so its out of the grid.
Then for I-78 (if it had gone through Manhattan, Brooklyn, and Queens) had I-278 to the west, then I-478, I- 678, and finally I-878 all from West to east just like the mileage and exit numbering.
Although Florida for I-95 odd spurs are awkward, like I-195 north of I-395 and then I-595.
Quote from: sp_redelectric on December 03, 2012, 03:30:45 PM
Washington State has just three 3dis - I-205 (whose southern end is in Oregon), I-405 around the east side of Seattle, and I-705 in Tacoma. Why no I-105?
It's to not conflict with state routes. SR 105, 305, and 505 all exist. (Also, it serves as a continuation of SR 7 -- I think that's more of a coincidence, though, and the first thing I said is the actual reason.)
Quote from: Kacie Jane on December 03, 2012, 05:08:57 PM
It's to not conflict with state routes. SR 105, 305, and 505 all exist. (Also, it serves as a continuation of SR 7 -- I think that's more of a coincidence, though, and the first thing I said is the actual reason.)
the state routes were numbered that way in 1964, correct? when did WA decide on its interstate numbers?
I-705 was legislatively created in 1979 (it wasn't an original Interstate).
Connecticut uses the following:
I-384 from I-84 Exit 59 in East Hartford to US Routes 6 and 44 in Bolton.
I-684 in Greenwich, mostly between exits 2 and 3 in Westchester County, NY.
I-291 from I-91 Exit 35A in Windsor to I-84 Exit 61 in Manchester.
I-691 from I-91 Exit 17 (NB) and 18 (SB) in Meriden to I-84 Exit 27 at the Cheshire/Southington town line.
I-395 from Exit 76A (NB) in East Lyme to the MA state line in Thompson.
How about I-481 in New York and I-587/I-787? Maybe it's worth trying to complete this list. I-393 NH is another.
187 and 387 both existed at one point, though, correct?
Quote from: Kacie Jane on December 03, 2012, 06:28:59 PM
187 and 387 both existed at one point, though, correct?
"On Aug. 22, 1958, the New York Department of Public Works submitted "Interstate 387" for the New York State Thruway between Elmsford and Suffern. On Aug. 29, 1958, AASHO replied that this should be called I-287 and connect to a proposed I-287 in New Jersey."
I know nothing of I-187.
I've looked this up dozens of times, yet can never remember the answer when it inevitably comes up again. 187 and 387 were both proposed numbers for I-287 in New York (187 east of I-87 in Elmsford, 387 west of there -- 87 at the time still planned to stay east of the Hudson). However, AASHO said no, and when the highway was finished, it was signed as 287 west of Elmsford, and 487 east of Elmsford, with 287 quickly usurping the whole route.
So according to Kurumi's site, I-187 and I-387 existed, but only on paper, and for only about a week.
Quote from: Steve on December 03, 2012, 07:34:38 PM
"On Aug. 22, 1958, the New York Department of Public Works submitted "Interstate 387" for the New York State Thruway between Elmsford and Suffern. On Aug. 29, 1958, AASHO replied that this should be called I-287 and connect to a proposed I-287 in New Jersey."
I know nothing of I-187.
I'm curious where you got that quote from, Steve, as wherever it was should have had a nearly identical quote regarding 187.
http://www.kurumi.com/roads/3di/ix87.html
187, 387, and 587 (and probably 787) were all proposed in 1958. 187 and 387 became 487 and 287, but 587 remained.
If I-587 was proposed at the same time, that explains perfectly why they still skipped over 187 and 387 even though they were never signed. No sense changing the number if AASHO doesn't make them.
Quote from: Takumi on December 03, 2012, 01:01:48 PM
Virginia seems to just not want to disrupt its numbering system anymore. The last Virginia state route renumbered for a 3di was VA 195 (now 186) in the 1970s. Since then I-564 was created with VA 164 and 364 already extant. I-785 will just be an extension of NC's, and the proposed I-895 (now VA 895) was chosen over 695 because Chesterfield County didn't have an SR 895 but does 695.
I-364 was on the board early on but became I-464. Additionally, I-564 was on the drawing board with that number before VA 364 was created in 1968.
Mapmikey
With regards to the x81s, there is continuity across states and they increase from south to north. Virginia uses 381 and 581, skipping 181 because it already existed in Tennessee (until I-26 ate it). Likewise, New York is numbering its new spur 781 so as to continue the trend and not reuse any of the other numbers.
As for 481, Interstate Guide (http://www.interstate-guide.com/i-481_ny.html) hypothesizes that 281 wasn't used because NY 281 was already nearby. Seems reasonable.
I-284 and I-484 were both planned in Hartford but never built, leaving 684 as an oddity. I-384 was numbered such no doubt because CT 184 already exists and Connecticut does not allow duplicate numbers. Ditto for I-395 - CT 195 already exists. Actually, CT 184 and CT 195 themselves were CT 84 and CT 95 before the interstate system invaded and took their numbers.
Quote from: Kacie Jane on December 03, 2012, 07:44:14 PM
Quote from: Steve on December 03, 2012, 07:34:38 PM
"On Aug. 22, 1958, the New York Department of Public Works submitted "Interstate 387" for the New York State Thruway between Elmsford and Suffern. On Aug. 29, 1958, AASHO replied that this should be called I-287 and connect to a proposed I-287 in New Jersey."
I know nothing of I-187.
I'm curious where you got that quote from, Steve, as wherever it was should have had a nearly identical quote regarding 187.
I'm curious why I didn't scroll up past 287 to see the 187 on top.
@ DUKE87: How convenient with I-684, huh? Despite the fact that over 95% of the road is in New York!
Quote from: KEVIN_224 on December 03, 2012, 09:54:09 PM
@ DUKE87: How convenient with I-684, huh? Despite the fact that over 95% of the road is in New York!
There was still a conflict when the highway originally opened, as I-87. Connecticut was preparing to renumber CT 87 as 287 but was able to abandon that when I-87 changed numbers instead.
States try to avoid having 2 of the same 3DIs in consecutive states or within 100 miles of each other along the mainline of 2DI's. CT chose I-395 over I-195 to avoid confusion with the I-195 in RI/MA. At one point, I-195 was to be extended to I-295 in Johnston, RI, which at its closest point is less than 30 miles from I-395 in Killingly, CT. Also, I-395 goes into MA up to the Mass Pike, so there'd be some real confusion with 2 195's in MA unless the I-290 designation were carried south to the CT line. Examples of x95's from south to north
195: FL, VA, NJ (PA), RI/MA, ME
295: FL, NC, VA/MD, DE/NJ, NY, RI/MA
395: FL, VA/DC, CT/MA, ME
495: MD/VA/DC, DE, NY, MA, ME
595: FL, MD (hidden)
695: DC, MD, NY
795: FL (future), NC, MD
895: VA, MD, NY
The only real exception here would be the 695's, but the DC one was a recent addition.
Quote from: jp the roadgeek on December 04, 2012, 12:02:13 AM
The only real exception here would be the 695's, but the DC one was a recent addition.
As a signed route, yeah. As an actual designation? DC's I-695 has existed much longer:
http://en.wikipedia.org/wiki/Interstate_695_(Washington,_D.C.)
Of course, going back to Connecticut, its I-291 is not that far from the Massachusetts route of the same number.
Quote from: jp the roadgeek on December 04, 2012, 12:02:13 AM
The only real exception here would be the 695's, but the DC one was a recent addition.
No it was not. It may have only recently been signed for the first time, but it's existed since 1958.
Some states are picky about not using the same number twice regardless of classification, so they let piddly state highways on the other side of the state guide their 3di selection. Once upon a time, Wisconsin was one of these states. Then we got I-39. Now we want I-41. We correctly abandoned that silly idea. Interstates should always trump US and state highway numberings.
The I-94 spurs in Milwaukee seem to have been chosen from the high end to distinguish them from sorta nearby Chicago and it's I-294 and then-proposed I-494.
Wasn't there something about an AM radio station involved in Ft. Worth's I-820?
I-41/US41 is the same route - like CA15/I-15 or whatever. It's not a duplication. But with you that it's a silly idea.
Quote from: english si on December 04, 2012, 10:23:53 AM
I-41/US41 is the same route - like CA15/I-15 or whatever. It's not a duplication. But with you that it's a silly idea.
74/74 will at one point have a signed split - one 74 going one way, one the other. it may even be the case already.
I think NY spaces it's 3di's so that if they were to add some they would still fit the consecutive system. I-87 and I-81 both seem to fit this. I-84 is again the anomaly though, as I-684 would be I-884 in a strict application of this.
Quote from: triplemultiplex on December 04, 2012, 09:43:25 AM
Wasn't there something about an AM radio station involved in Ft. Worth's I-820?
That's a maybe, involving WBAP 820 AM. I haven't seen an authoritative source confirming it.
Another example... why is I-474 in Illinois (around Peoria) not I-274?
Quote from: Duke87 on December 03, 2012, 08:58:09 PM
With regards to the x81s, there is continuity across states and they increase from south to north. Virginia uses 381 and 581, skipping 181 because it already existed in Tennessee (until I-26 ate it). Likewise, New York is numbering its new spur 781 so as to continue the trend and not reuse any of the other numbers.
....
The I-x81 situation in Virginia also came about because of the proximity of I-381 to I-181–it's only about 22 miles between those two interchanges via essentially a straight shot on I-81 and so the desire to avoid duplication was quite understandable.
Quote from: jp the roadgeek on December 04, 2012, 12:02:13 AM
States try to avoid having 2 of the same 3DIs in consecutive states or within 100 miles of each other along the mainline of 2DI's. CT chose I-395 over I-195 to avoid confusion with the I-195 in RI/MA. At one point, I-195 was to be extended to I-295 in Johnston, RI, which at its closest point is less than 30 miles from I-395 in Killingly, CT. Also, I-395 goes into MA up to the Mass Pike, so there'd be some real confusion with 2 195's in MA unless the I-290 designation were carried south to the CT line. Examples of x95's from south to north
195: FL, VA, NJ (PA), RI/MA, ME
295: FL, NC, VA/MD, DE/NJ, NY, RI/MA
395: FL, VA/DC, CT/MA, ME
....
The only real exception here would be the 695's, but the DC one was a recent addition.
There's also an I-195 near Baltimore (connects I-95 to BWI Airport) and an I-395 in downtown Baltimore (minuscule stub route that more or less connects I-95 to the Inner Harbor/ballpark area). Of course the Virginia/DC I-395 was originally I-95.
I-295 does not enter both Virginia and Maryland–it's two separate routes. Virginia's is a partial beltway around Richmond and Petersburg; Maryland's enters DC and connects I-95/495 to DC's I-695. Without looking it up I'm pretty positive the latter route existed first.
I'm pretty sure (again without looking it up) that Maryland has used more x95s than any other state–the only one they don't have is an I-995.
Quote from: triplemultiplex on December 04, 2012, 09:43:25 AM
Some states are picky about not using the same number twice regardless of classification, so they let piddly state highways on the other side of the state guide their 3di selection. Once upon a time, Wisconsin was one of these states. Then we got I-39. Now we want I-41. We correctly abandoned that silly idea. Interstates should always trump US and state highway numberings.
It's not silly. Duplicating route numbers creates confusion giving directions, reporting location when calling 911, discussing highways among officials and legislators, creating reports like statistics for every route in a state, etc., etc.
If an interstate needs a number, a state route may need its number changed, but if there's an available number for an interstate it's only common sense to use the number that would not require a number change.
Quote from: kkt on December 04, 2012, 01:51:44 PM
Quote from: triplemultiplex on December 04, 2012, 09:43:25 AM
Some states are picky about not using the same number twice regardless of classification, so they let piddly state highways on the other side of the state guide their 3di selection. Once upon a time, Wisconsin was one of these states. Then we got I-39. Now we want I-41. We correctly abandoned that silly idea. Interstates should always trump US and state highway numberings.
It's not silly. Duplicating route numbers creates confusion giving directions, reporting location when calling 911, discussing highways among officials and legislators, creating reports like statistics for every route in a state, etc., etc.
If an interstate needs a number, a state route may need its number changed, but if there's an available number for an interstate it's only common sense to use the number that would not require a number change.
It does make sense to change the number. When I-86 was proposed to go through southern MA they changed Route 86 in Salisbury--the northeasternmost town in the state-- to Route 286. Out of respect and to avoid confusion New Hampshire did the same on their Route 286--the same road as MA 286. Then they changed it to I-84.
Quote from: 1995hoo on December 04, 2012, 12:33:29 PM
I-295 does not enter both Virginia and Maryland–it's two separate routes. Virginia's is a partial beltway around Richmond and Petersburg; Maryland's enters DC and connects I-95/495 to DC's I-695. Without looking it up I'm pretty positive the latter route existed first.
VA I-295 was authorized at the inception of the Interstate highway system in 1956. The southern end would have been at I-95 near Chester. The extension to south of Petersburg was authorized in 1977.
QuoteIf an interstate needs a number, a state route may need its number changed, but if there's an available number for an interstate it's only common sense to use the number that would not require a number change.
I'd say there's a balancing point- if an I-202 were ever, for some crazy reason commissioned in Washington, and that was the number that made the most sense, it probably would make sense to re-evaluate whether 202 was necessary to be the number of that freeway, since 202 is already a pretty major state highway and maybe I-402 is available. If an I-971 were ever commissioned, and that was the number that made the most sense for the freeway, it would make sense to change the number of SR 971, since I doubt many people care that 971 is numbered 971.
Seems to me that state DOT's leave out certain numbers for one of three reasons, or possibly all:
a. There's already a state route with the omitted 3di number; or
b. The numbers are being reserved for future use.
c. The DOT wants to avoid potential confusion with a similar-numbered 3di in another state
Which leads me to wonder: Had the original I-595 in MD (cancelled I-170) been completed as planned, what would they do with the currently-designated one? I'm suspecting I-995, and still keep it hidden.
Another interesting note is I-85 spurs, which seem to have been randomly numbered at will.
I-185: Spurs to Columbus, GA, and Greenville, SC
I-285: Loop around Atlanta, GA
I-385: Spur to Greenville, SC
I-485: Loop around Charlotte, NC
I-585: Spur to Spartanburg, SC
I-785: Greensboro, NC-Danville, VA
I-985: Spur to Gainesville, GA
Note that this does not include the I-285 spur into Winston-Salem, NC or I-685 in Montgomery, AL, both future routes. I'm suspecting that it'll only be a matter of time before we see an I-885 somewhere, but I wouldn't hold my breath.
Quote from: MVHighways on December 04, 2012, 02:26:52 PM
It does make sense to change the number. When I-86 was proposed to go through southern MA they changed Route 86 in Salisbury--the northeasternmost town in the state-- to Route 286. Out of respect and to avoid confusion New Hampshire did the same on their Route 286--the same road as MA 286. Then they changed it to I-84.
I believe MA-295, in the northwest corner of the state, was allowed to keep its number.
Quote from: Henry on December 04, 2012, 03:17:54 PM
Which leads me to wonder: Had the original I-595 in MD (cancelled I-170) been completed as planned, what would they do with the currently-designated one? I'm suspecting I-995, and still keep it hidden.
The US-50 John Hanson Highway's first Interstate designation was to have been I-68.
Quote from: corco on December 04, 2012, 02:35:03 PM
I'd say there's a balancing point- if an I-202 were ever, for some crazy reason commissioned in Washington, and that was the number that made the most sense, it probably would make sense to re-evaluate whether 202 was necessary to be the number of that freeway, since 202 is already a pretty major state highway and maybe I-402 is available. If an I-971 were ever commissioned, and that was the number that made the most sense for the freeway, it would make sense to change the number of SR 971, since I doubt many people care that 971 is numbered 971.
The planners shouldn't start with saying "We need I-202." They should start with saying "We need a loop route off I-2." Then they find the best number for it. They'd go through 402, 602, 802, and if none of them worked they'd consider 102 to 902. If all of them were taken, then it would be time to renumbering the existing WA-202.
Quote from: agentsteel53 on December 04, 2012, 03:29:35 PM
Quote from: MVHighways on December 04, 2012, 02:26:52 PM
It does make sense to change the number. When I-86 was proposed to go through southern MA they changed Route 86 in Salisbury--the northeasternmost town in the state-- to Route 286. Out of respect and to avoid confusion New Hampshire did the same on their Route 286--the same road as MA 286. Then they changed it to I-84.
I believe MA-295, in the northwest corner of the state, was allowed to keep its number.
That is correct. Of course, MA 295 is only two miles long and has the sole purpose of connecting NY 295 to MA 41 in Richmond, MA. Given this, as well as its physical distance from I-295 within MA/RI, and the fact it doesn't intersect with any interstates (like old MA 86/current MA 286), it's a logical exception to the "no routes with same number" rule.
Quote from: Henry on December 04, 2012, 03:17:54 PM
Seems to me that state DOT's leave out certain numbers for one of three reasons, or possibly all:
....
c. The DOT wants to avoid potential confusion with a similar-numbered 3di in another state
....
This prompts me to think of the unusual situation in the District of Columbia, where DC-295 (the only road that bears a "territorial highway" number) was given that number specifically
because it was the same as an already-existing Interstate–it connects I-295 on the southern end and MD-295 on the northern end, although when the DC route number was first posted I-295 continued across the Anacostia River to a stub end at Barney Circle (it's now been truncated to end where it becomes DC-295). The idea of providing continuity to motorists with the "295" number all the way through trumped the potential confusion.....and it's not just motorists who might confuse the numbers, as some local media reports as recently as last week mixed up the "DC" portion with the Interstate portion.
Like IL-255, I guess.
Quote from: A.J. Bertin on December 04, 2012, 11:56:26 AM
Another example... why is I-474 in Illinois (around Peoria) not I-274?
My best guess on that has to do with routings around the Quad Cities.
I think I-255was numbered like a bypass and then extended and for some crazy reason it hasnt been given an interstate degination all the way even though it is more like a spur.
Illinois did want to use x74 numbers for the Quad Cities . The numbering fight with Iowa is old(my current idea is to extend 88 to Iowa and 188 to Monmouth) This brings me to 174, IDOT did try to get that for US 34 Galesburg-Monmouth
Quote from: Beltway on December 04, 2012, 05:32:48 PM
Quote from: kphoger on December 04, 2012, 04:29:29 PM
Like IL-255, I guess.
Like VA-381
More examples:
NY 890, NY 690, NY 590, NY 390, NY 787, NY 481
Route 110 in California
PA 283
BY 1960, Minnesota renumbered its existing state highways that duplicated the interstate numbers: 35, 90, 94, in each case by appending "1". It did not use existing three-digit state route numbers, though for 3di interstates; I-494 was established instead of 294, which was an already existing very minor route serving a state facility in Willmar. And, a proposed route north of downtown Minneapolis that was ultimately shelved was designated I-335 instead of 135, even though that route was itself created in place of old state route 35. That is why the lowest odd prefix I-x35 is 535.
Quote from: roadman65 on December 03, 2012, 04:59:12 PM
This would explain a lot. I never thought of it, but there is a pattern of the way the first numbers are selected as I can see in New York for I-90 spurs going from 1 to 8 from West to East, and then I-990 was added later so its out of the grid.
Then for I-78 (if it had gone through Manhattan, Brooklyn, and Queens) had I-278 to the west, then I-478, I- 678, and finally I-878 all from West to east just like the mileage and exit numbering.
I seem to recall a related thread about which states number their 3dis in geographical sequence, and NY is obviously one of them. Although it's most apparent with the x90s, I think the same practice is seen applied with x87s: I-587 and I-787 are where you'd expect them to be, allowing for 187 and 387 farther downstate (regardless of whether either of those were actually proposed). I-481 was originally to be numbered 281, but it was changed perhaps not so much because of nearby NY 281 (as state routes have a tendency to be renumbered in favor of duplicate Interstate numbers) but to allow for a possible I-281 in Binghamton.
Quote from: empirestate on December 04, 2012, 08:43:42 PM
I seem to recall a related thread about which states number their 3dis in geographical sequence, and NY is obviously one of them.
Michigan kinda does this with the x96's... from west to east, you have I-196, then the hidden I-296, then I-496, then I-696.
Not sure if Louisiana has been mentioned yet, but I-x10s in Louisiana seem to be in order from west to east:
I-210 in Lake Charles
I-110 in Baton Rouge
I-310 west of New Orleans
I-610 in New Orleans
I-510 east of New Orleans
It works if you think of the spurs and loops as two separate lists. This could provide an I-410 in Baton Rouge, and even an I-810 in New Orleans or Slidell.
This also doesn't take into account the hidden I-910 on the Crescent City Connection/Pontchartrain Expressway/Westbank Expressway, but perhaps the number "910" was picked because it was intended to be hidden and wouldn't create a numbering gap somewhere if this is what Louisiana was going for?
As for Nebraska, the only reason there is not an I-280 is because what is now I-680 was supposed to go into Iowa, where there already was an I-280. That leaves unexplained why what is now the North Freeway (currently US 75) in Omaha was going to be I-580. They must have thought the North Freeway would go into Iowa as well, negating the ability to name it I-380. (FWIW, I think that would be a reasonable freeway construction, not that it's going to happen anytime soon.)
In Iowa, the mystery Interstate designation is I-380. Obviously, at least to me, it should be I-180, although Illinois and Nebraska have those as well. But the thing about Iowa is, at least by looking at Jason Hancock's Iowa highway website, IA 129, IA 235, and IA 280 all existed (as did IA 380) before the numbers were reassigned to the current interstates (presumably, so did 29, 35, 74 and 80, but I didn't look those up). So why they didn't change it to 180 is presumably to avoid confusion with its neighboring states, although I'm not sure how one can be confused.
Quote from: A.J. Bertin on December 03, 2012, 12:35:22 PM
It seems like there are many occasions where 3-digit interstates are numbered a bit strangely. The DOTs (or whatever agency is responsible for selecting highway numbers) have made some strange choices. For the 3-digit interstate highways, either four digits (2, 4, 6, or 8 - in the case of loops) or five digits (1, 3, 5, 7, or 9 - in the case of spurs) are available. There are many occasions where I higher digit was selected when lower digits are available.
Here are a few examples I've noticed:
I-375 in Detroit, MI - why not I-175?
I-516 in Savannah, GA - why not I-116?
I-675 outside Atlanta, GA - why not I-475?
I-794 in Milwaukee, WI - why not I-594?
I-459 in Birmingham, AL - why not I-259?
I-520 in Augusta, GA - why not I-120?
I-820 in Fort Worth, TX - why not I-620?
I-530 in Arkansas - why not I-130?
I-684 in New York and Connecticut - why not I-284?
I-691 in Connecticut - why not I-491?
These are just some examples of what I'm talking about. I don't know why this bothers me, but it just does. LOL
I can answer the I-520 question. The reason why there is no I-120 is because the BOBBY JONES EXPWY now extends into North Augusta, SC - and there is an SC 120 in the state in Sumter County. Either GDOT or SCDOT, or both, want to avoid using the same route numbers for Interstate and State Routes as much as possible. Hence, why there are only a handful of highways that have the same number for Interstate and State Routes in SC. I-126 in Columbia and BELVEDERE-CLEARWATER RD (SC 126) in Aiken County, as well as I-20 and SC 20, are rarities.
Quote from: mjb2002 on December 08, 2012, 09:37:00 PM
I can answer the I-520 question. The reason why there is no I-120 is because the BOBBY JONES EXPWY now extends into North Augusta, SC - and there is an SC 120 in the state in Sumter County.
??? I-520 was only in Georgia for a long time.
Quote from: mjb2002 on December 08, 2012, 09:37:00 PM
I can answer the I-520 question. The reason why there is no I-120 is because the BOBBY JONES EXPWY now extends into North Augusta, SC - and there is an SC 120 in the state in Sumter County. Either GDOT or SCDOT, or both, want to avoid using the same route numbers for Interstate and State Routes as much as possible. Hence, why there are only a handful of highways that have the same number for Interstate and State Routes in SC. I-126 in Columbia and BELVEDERE-CLEARWATER RD (SC 126) in Aiken County, as well as I-20 and SC 20, are rarities.
South Carolina does not care about interstate routes having numbers already in the state highway system. They only changed SC 77 and SC 85 because North Carolina had this policy.
South Carolina retains SC 20, SC 126, SC 185, SC 385
SC 26, SC 95 and SC 526 were renumbered/retired before the interstate era. SC 73 appears to also have been recently decommissioned (not renumbered).
Additionally, Georgia has coincidental state route designations for all of its 2di numbers and I-185 and has a prominent GA 520 which came years after I-520 was in place.
It seems to me that the 516 and 520 designations fit the geography dynamic where 1xx and 3xx are reserved for potential use further west on those interstates.
Mapmikey
I've always wondered why the beltway around Topeka was numbered I-470 instead of I-270. I always thought it odd especially considering there's an I-470 in the Kansas City area. But Topeka's I-470 meets its parent at both ends while Kansas City's only meets it at its farthest east point, so maybe confusion isn't likely.
Richie, you ever heard anything about why Kansas' I-470 is numbered as it is?
Quote from: corco on December 03, 2012, 12:46:08 PM
But that's why San Antonio is I-410 and Houston is I-610, I think, so that El Paso could have I-210 if ever necessary.
I-210 would be a potential number for Loop 375 in El Paso if it were upgraded to interstate standards.
Quote from: Ace10 on December 07, 2012, 03:24:33 PM
This also doesn't take into account the hidden I-910 on the Crescent City Connection/Pontchartrain Expressway/Westbank Expressway, but perhaps the number "910" was picked because it was intended to be hidden and wouldn't create a numbering gap somewhere if this is what Louisiana was going for?
It's plausible whether I-910 was picked to align with US 90 BUS.
Quote from: A.J. Bertin on December 04, 2012, 11:56:26 AM
Another example... why is I-474 in Illinois (around Peoria) not I-274?
Peoria has 474 because 274 was reserved for the Quad Cities. On paper Interstate 274 was intended for the current stretch of I-80 from I-74's west end to the I-74/280 junction to the southeast of Quad Cities. In this plan I-74 and 80 shared pavement through the heart of the QC. AASHO replaced I-274 with a realigned I-80 on November 10, 1958.
Wisconsin comes to mind with this thread. Why jump to 894 and 794 in the Milwaukee area, when 1-6 were available as prefixes for 94 statewide.
Here's another subject to ponder: I-30.
I-430, I-530 and I-630 exist (as will I-130 in a few years), but I-230 and I-330 do not. One has to wonder why this is so.
Quote from: Henry on December 10, 2012, 02:32:46 PM
Here's another subject to ponder: I-30.
I-430, I-530 and I-630 exist (as will I-130 in a few years), but I-230 and I-330 do not. One has to wonder why this is so.
I'm pretty sure 130 was in the books as a potential spur for Texarkana on AR 245 before more was completed on I-49. Then they realized that 49 would use most of that roadway. I think Kurumi's site may attest to this.
Quote from: OCGuy81 on December 10, 2012, 02:12:12 AM
Wisconsin comes to mind with this thread. Why jump to 894 and 794 in the Milwaukee area, when 1-6 were available as prefixes for 94 statewide.
My theory from upthread:
Quote
The I-94 spurs in Milwaukee seem to have been chosen from the high end to distinguish them from sorta nearby Chicago and it's I-294 and then-proposed I-494.
With 794, I have noticed that if there was a spur from I-94 into Kenosha, another into Racine and interstate status for MKE's airport spur, one would have sequential odd spurs increasing south to north. At some point, there were east-west freeways proposed between I-94 and the once-proposed Lake Freeway in both Racine and Kenosha.
Or if one was numbering spurs of I-94 west to east, Milwaukee would be near the west end and given higher x94's.
Quote from: DandyDan on December 08, 2012, 02:24:09 AM
As for Nebraska, the only reason there is not an I-280 is because what is now I-680 was supposed to go into Iowa, where there already was an I-280.
That, and that the only 3dis in Omaha would cross into Iowa.
Quote from: DandyDan on December 08, 2012, 02:24:09 AMThat leaves unexplained why what is now the North Freeway (currently US 75) in Omaha was going to be I-580. They must have thought the North Freeway would go into Iowa as well, negating the ability to name it I-380. (FWIW, I think that would be a reasonable freeway construction, not that it's going to happen anytime soon.)
I think (and I have no legitimate basis for saying this) that maybe 5 was used because it was close to the other two 3di numbers in Omaha.
Quote from: pianocello on December 10, 2012, 07:18:02 PM
Quote from: DandyDan on December 08, 2012, 02:24:09 AM
As for Nebraska, the only reason there is not an I-280 is because what is now I-680 was supposed to go into Iowa, where there already was an I-280.
That, and that the only 3dis in Omaha would cross into Iowa.
Quote from: DandyDan on December 08, 2012, 02:24:09 AMThat leaves unexplained why what is now the North Freeway (currently US 75) in Omaha was going to be I-580. They must have thought the North Freeway would go into Iowa as well, negating the ability to name it I-380. (FWIW, I think that would be a reasonable freeway construction, not that it's going to happen anytime soon.)
I think (and I have no legitimate basis for saying this) that maybe 5 was used because it was close to the other two 3di numbers in Omaha.
That, and also because I-180 in Lincoln and I-380 in Cedar Rapids already existed at the time.
Quote from: Ace10 on December 07, 2012, 03:24:33 PM
Not sure if Louisiana has been mentioned yet, but I-x10s in Louisiana seem to be in order from west to east:
I-210 in Lake Charles
I-110 in Baton Rouge
I-310 west of New Orleans
I-610 in New Orleans
I-510 east of New Orleans
It works if you think of the spurs and loops as two separate lists. This could provide an I-410 in Baton Rouge, and even an I-810 in New Orleans or Slidell.
This also doesn't take into account the hidden I-910 on the Crescent City Connection/Pontchartrain Expressway/Westbank Expressway, but perhaps the number "910" was picked because it was intended to be hidden and wouldn't create a numbering gap somewhere if this is what Louisiana was going for?
I-410 was originally planned for Baton Rouge; late 1950s state highway maps show current I-110 as 410.
I suppose the other way to ask the question is, why would you use the lowest number available? Besides satisfying a rather abstract desire to start from the beginning, it has the effect of numbering them chronologically by their construction date, which seems less useful than having a geographic sequence or some other rationale. Imagine if exits were given the next available number at the time they're opened; you'd have a pretty meaningless system! (And indeed, that's one of the complaints I most often hear about sequential exit numbering: that it leaves no room in the sequence for added interchanges.)
Do what most states (or at least the NJTA) do:
Exit 8, (drive, drive, drive...) newer, unrelated Exit 8A, (drive, drive, drive...) Exit 9...
Most people don't even realize that I-240 and I-40 are "related". I doubt it would even cross their mind that the numbers went in a particular order (the 2dis being in order never seems to occur to non-roadgeeks unless I point it out).
Quote from: kkt on December 04, 2012, 01:51:44 PM
It's not silly. Duplicating route numbers creates confusion giving directions, reporting location when calling 911, discussing highways among officials and legislators, creating reports like statistics for every route in a state, etc., etc.
When you duplicate route numbers across systems, you get silliness like this:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.millenniumhwy.net%2F2010_SEPA_Day_3%2FImages%2F588.jpg&hash=d420221cbf113e7a9f6477186e9bae1dfa5c38f6)
Quote from: empirestate on December 13, 2012, 01:25:38 AM
I suppose the other way to ask the question is, why would you use the lowest number available? Besides satisfying a rather abstract desire to start from the beginning, it has the effect of numbering them chronologically by their construction date, which seems less useful than having a geographic sequence or some other rationale. Imagine if exits were given the next available number at the time they're opened; you'd have a pretty meaningless system! (And indeed, that's one of the complaints I most often hear about sequential exit numbering: that it leaves no room in the sequence for added interchanges.)
Exactly.
Though growing up in California we were lucky when any 3di number was available for a spur or loop off its 2di, let alone having them be in a pattern of any sort.
Quote from: kkt on December 13, 2012, 12:33:58 PM
Though growing up in California we were lucky when any 3di number was available for a spur or loop off its 2di, let alone having them be in a pattern of any sort.
What I wonder: Is a geographic pattern why I-405 and I-605 were used before I-205, and why I-905 was chosen for the Otay Mesa spur instead of I-705?
Quote from: TheStranger on December 13, 2012, 01:05:36 PM
What I wonder: Is a geographic pattern why I-405 and I-605 were used before I-205, and why I-905 was chosen for the Otay Mesa spur instead of I-705?
the location of I-805 seems to confirm it, though I am not sure chronologically when 805 was designated, relative to 405 and 605.
however, why was 105 used as that brief segment of East LA Interchange in the beginning of the system, as opposed to 705?
Quote from: agentsteel53 on December 13, 2012, 01:14:10 PM
Quote from: TheStranger on December 13, 2012, 01:05:36 PM
What I wonder: Is a geographic pattern why I-405 and I-605 were used before I-205, and why I-905 was chosen for the Otay Mesa spur instead of I-705?
the location of I-805 seems to confirm it, though I am not sure chronologically when 805 was designated, relative to 405 and 605.
Looking at the Yellow Book scan from Froggie's page, 405, 605 both were planned in the earliest stages:
http://www.ajfroggie.com/roads/yellowbook/losangeles.jpg
Wikipedia notes in the I-805 article that that route was approved as an Interstate in 1958, so after 405/605 had first been proposed.
Quote from: agentsteel53
however, why was 105 used as that brief segment of East LA Interchange in the beginning of the system, as opposed to 705?
Looking at that above Yellow Book map, the 105/110 pair of 1964-1968 was part of the original planning, too - which is interesting given that that segment of the Santa Ana Freeway that was unsigned 105 has NEVER been upgraded to Interstate standards from what I recall.
That might explain why that was "105" as the original proposed first odd branch route from I-5. The only other odd 3di that I-5 had (until the FHWA creation of unsigned I-305 in 1982) was I-505 from 1964 onwards, whose number (as was 580's) was derived from the former designation of I-5W.
Quote from: Steve on December 03, 2012, 06:24:34 PM
How about I-481 in New York and I-587/I-787? Maybe it's worth trying to complete this list. I-393 NH is another.
I-481 was originally I-281, but NYSDOT wanted to avoid confusion with NY Route 281, which is about 20-25 miles south of I-481.
Quote from: upstatenyroads on December 14, 2012, 07:54:50 AM
Quote from: Steve on December 03, 2012, 06:24:34 PM
How about I-481 in New York and I-587/I-787? Maybe it's worth trying to complete this list. I-393 NH is another.
I-481 was originally I-281, but NYSDOT wanted to avoid confusion with NY Route 281, which is about 20-25 miles south of I-481.
The portion between the Thruway and its' southern terminus was, but the portion between the Thruway and NY 481's northern terminus was intended to be an extension of NY 57.
Quote from: hbelkins on December 13, 2012, 12:30:25 PM
Quote from: kkt on December 04, 2012, 01:51:44 PM
It's not silly. Duplicating route numbers creates confusion giving directions, reporting location when calling 911, discussing highways among officials and legislators, creating reports like statistics for every route in a state, etc., etc.
When you duplicate route numbers across systems, you get silliness like this:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.millenniumhwy.net%2F2010_SEPA_Day_3%2FImages%2F588.jpg&hash=d420221cbf113e7a9f6477186e9bae1dfa5c38f6)
Only if you don't take care to keep routes far enough apart that it isn't a concern. OK doesn't have an issue with there being an I-44 and an OK 44, a US 56 and an OK 56, a US 266 and an OK 266, etc. (US 270 and OK 270 are kind of confusing but US 270 is concurrent with I-40 at the bit where the conflict arises, so it's likely nobody is really looking for it.)