State numbering

[sandiaman]

  NEW  MEXICO  has  no  coherence  to its  numbering system for highways.  They  don't duplicate    federal or Interstate  numbers, but for some unknown reason,  once a number is retired, it is forever.  There is no rhyme  or reason,  but  if a highway  route number  is replaced, it is always  with  some long three  digit number that  has no  reference  to a parent highway.  Along state route numbers  such as SR 18, which used to be the longest state highway was replaced in  1988 by three  different  state highway route numbers that were not related .  They keep the original number from its southern or western  point of origin.

[agentsteel53]

New Mexico looks like they eliminated all multiplexes in their state highway system, which is how 18 ended up with several numbers (as did a lot of other formerly trans-state routes, like 3). 

[national highway 1]

New Mexico looks like they eliminated all multiplexes in their state highway system, which is how 18 ended up with several numbers (as did a lot of other formerly trans-state routes, like 3). 

Hmm.. What California tried to do in 1964, but yet we still have multiplexes!

[roadfro]

Hmm.. What California tried to do in 1964, but yet we still have multiplexes!

Not officially, you don't.

[Bickendan]

Case in point: The Golden Gate Bridge officially has no routes on it; US 101 and CA 1 are signed across it for motorist convenience.

[mightyace]

Case in point: The Golden Gate Bridge officially has no routes on it; US 101 and CA 1 are signed across it for motorist convenience.

I didn't know that.  So, officially, US 101 and CA 1 have a gap in them?

[J N Winkler]

NEW  MEXICO  has  no  coherence  to its  numbering system for highways.

There is a logic to it, actually, but you need to have a copy of the 1912 state highway map in order to see the underlying pattern, which was severely disrupted by the US highways and by the 1988 renumbering.

They  don't duplicate federal or Interstate  numbers, but for some unknown reason,  once a number is retired, it is forever.

This is not always true--NM 1 is such a "revived" number.  I think the main reason numbers are not recycled is to allow similar "revivals" within the same general corridor as the original number.

There is no rhyme  or reason,  but  if a highway  route number  is replaced, it is always  with  some long three  digit number that  has no  reference  to a parent highway.

As Steve Riner pointed out upthread (and I have pointed out in the past in MTR), the new three-digit number will typically have as its first digit the number of the NMDOT district.  Each NMDOT district has a block of up to 100 route numbers which are available for assignment to state highways within that district which need renumbering.  Numbers already assigned are withdrawn from the block and the remainder are assigned more or less in sequence as they are needed.  Most allocations out of these blocks were made during the course of the 1988 renumbering and as a result, for example, new 1988 numbers start in the high mid-100's in District 1 (southwestern NM) and in the very low 600's in District 6 (northwestern NM).

NM 2001 (probably a reference to 2001:  A Space Odyssey) and NM 6563 (Balmer transition!) are true outliers.  NM 6563 was originally supposed to be NM 248 (since it is in District 2 and received its current number during the course of the 1988 renumbering).

In addition to the primary state highways in NM, the state-maintained frontage roads constitute a state secondary highway system with its own shield (NM state outline on black background).  Frontage roads have four-digit numbers, with the first two digits being typically the route number of the freeway mainline (so, for example, US 70 in Las Cruces might have frontage roads numbered 7000 and above).  Frontage roads are rarely explicitly signed with shields but there are some examples in the field, notably on I-10 in southwestern NM.  It is my understanding that NM has had other routes numbered between 9990 and 9999 but this is based on six-year-old information and these routes may no longer exist if they were being used as temporary designations for lengths of state highway which NMDOT wanted to offload onto localities.

[J N Winkler]

I didn't know that.  So, officially, US 101 and CA 1 have a gap in them?

SR 1 has multiple gaps in it, as do quite a few other state routes.  All California state routes are defined in the Streets and Highways Code.  You see quite a few definitions of the form:  "Route X is from:  (a) A to B; (b) C to D; (c) E to F; . . ."  But Caltrans tends to sign routes across gaps in the route definition as if the route existed across the gap (SR 49/89 in the Sierras being one example), without using a "TO" tab.  The reason for this is that until Caltrans adopted the FHWA manual with a supplement in 2004, the Caltrans Traffic Manual restricted the use of "TO" tabs to signing the way to a freeway.  This restriction no longer exists but I am not personally aware of any field examples of "TO" being used otherwise than to lead to a freeway.

[Mapmikey]

The number appears to have been a coincidence, as froggie said.

VA 895 was numbered as such because the way it was planned and funded meant it could not become an interstate highway, at least for as long as it remains a toll road. Presumably if tolls are ever removed, it could become I-895, but Transurban has a 99-year lease on the highway, so assuming it doesn't lose that lease somehow, we'll be into the 2100s before I-895 becomes reality in Virginia.

VA 195 was numbered as an extension of I-195 and is maintained by the Richmond Metropolitan Authority (which now signs the beginning and end of its area of maintenance - it does this with VA 76, too).

VA 785 is a placeholder for I-785, should it ever come into being in Virginia. It isn't signed, although "Future I-785" is.

According to the VHP, back when dinosaurs ruled the earth, three-digit state highways in Virginia were usually spurs of two-digit routes (sometimes one-digit routes, which caused confusion), and seem to have been numbered in the order of their creation - the first spur of VA 30 was VA 301, the second was VA 302, etc. This could extend past 10 - the 10th spur of VA 10 was VA 1010, and there were also a VA 1011 and a VA 1012. A spur of a spur (the first VA 311, which is now part of VA 54) got numbered as VA 3111, one of the highest numbered primary routes ever to exist.

The only current rule seems to be that primary/U.S./interstate routes cannot duplicate secondary route numbers, even though this probably isn't even a rule at all - it's just hard for this to happen since the SR's start at 600. There is no SR 895 in Chesterfield County (Henrico has no SR's). There was not a SR 664 in Suffolk when Suffolk still officially had SR's, but there IS a SR 785 in Pittsylvania County, though I'm not sure VA 785 enters the county.

I just re-read what I wrote for the history of renumbering and I definitely need to re-write it.  There are some inaccuracies in it.

To clarify a little, 3-digit routes as described above did not co-exist with single digit routes, which did not exist in Virginia 1923-33.  Spurs off routes (1 or 2 digit) from 1918-23 were suffixes (W,X,Y,Z were used) or simply SPUR which on maps were shown as if they were the mainline route.

There were 5 explicitly known 4-digit routes 1923-28: 1010, 1011, 1012, 1141 and 3111.  A 6th, 1013, was likely to have existed but I have not been able to prove it definitively.

VA 195 was a renumbering of VA 88 which occurred before any of it was opened.

I believe it -is- a rule that primary routes be numbered under 600.  The basis for this is that the 2001 and 2003 route logs list all numbers that are in use and all numbers that are NOT (with NOT ASSIGNED).  This list stops at 599.  VA 895 is an anomaly/exception.  It isn't the first time Virginia has violated its rules of numbering.

Suffolk SR 664 was renumbered as SR 759 (this is W. Liberty Spring Rd off US 13; Quaker Rd; Pineview Rd; Gates Rd in a loop southwest to the NC Line.  Google Maps still shows the stub from Pittmantown Rd SR 668 to NC as SR 664 - http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=suffolk,+va&sll=37.0625,-95.677068&sspn=52.550571,90.175781&ie=UTF8&hq=&hnear=Suffolk,+Virginia&ll=36.553155,-76.812801&spn=0.013152,0.022016&t=h&z=16

I cannot find a Chesterfield SR 895 in the 1958 VDOT atlas and it does not show in the 2001 traffic log either.

While Henrico County has not ever had VDOT-maintained secondary roads, for years they had inventory numbers that mimicked the SR-numbering system.  Official maps in the 50s-60s showed them and the 1958 Henrico County map shows all of them.  There was no SR 895 in 1958 there either.

If VA 785 still ends at the US 29-58-360 interchange, the entire route is within the City of Danville.

Mapmikey

[agentsteel53]

NM 6563 (Balmer transition!)

I never realized that! 

now, what's Florida 9336?

[agentsteel53]

Case in point: The Golden Gate Bridge officially has no routes on it; US 101 and CA 1 are signed across it for motorist convenience.

about the one place where the ultimate goal of signed routes - motorist convenience - is noted. 

How many other states say "well, we can't sign this route because it's not part of the legislated network - never mind that the road is completely up to standard and it would make a lot of sense to give this number to this corridor"? 

Case in point: further south in California, highway 39, with a gap in it.  County N8 is the gap, and it is a perfectly good urban arterial, with the same quality as the ends of 39 that touch it at the north and south. 

(Meanwhile, further north, highway 39 is still signed, but there's a large barricade across the road because of a landside ... that took place in the 1970s.)

[TheStranger]

I didn't know that.  So, officially, US 101 and CA 1 have a gap in them?

SR 1 has multiple gaps in it, as do quite a few other state routes.  All California state routes are defined in the Streets and Highways Code.  You see quite a few definitions of the form:  "Route X is from:  (a) A to B; (b) C to D; (c) E to F; . . ."  But Caltrans tends to sign routes across gaps in the route definition as if the route existed across the gap (SR 49/89 in the Sierras being one example), without using a "TO" tab.  The reason for this is that until Caltrans adopted the FHWA manual with a supplement in 2004, the Caltrans Traffic Manual restricted the use of "TO" tabs to signing the way to a freeway.  This restriction no longer exists but I am not personally aware of any field examples of "TO" being used otherwise than to lead to a freeway.

There's one very notable example: "TO 99" on westbound US 50/Business 80 (and northbound Route 99) at the I-5 junction.  (There is also a mix of "TO 99" and "99" signage southbound on I-5 from about J Street to US 50.)  North of J Street, the route is somewhat more consistently signed as I-5/Route 99 - in the few instances Route 99 shields appear.

about the one place where the ultimate goal of signed routes - motorist convenience - is noted. 

How many other states say "well, we can't sign this route because it's not part of the legislated network - never mind that the road is completely up to standard and it would make a lot of sense to give this number to this corridor"? 

Funny thing is, IIRC, Route 1/US 101 are not signed on the bridge itself - BUT are signed from the toll plaza south, and from the Marin landing north.  Which still beats your example of the Route 39 gap...(amusing considering that Route 39 was proposed as a unified route through Fullerton in the 1930s, but that maintenance/signage gap has existed as far back as the 1940s!)

Other cases in which a co-routing/gap is not acknowledged via any signage:

Route 193
Route 16
Route 1 through Santa Barbara County
Route 271 north of Route 1

There are also many examples of existing corridors along unsigned/proposed routes that could be signed for motorist convenience, but aren't at all (i.e. Route 93, Route 77, Route 47 north of Route 91).

[Scott5114]

Because Oklahoma has never undergone a complete, system-wide renumbering, the current route system has organically evolved from the original August 1924 route system. You can find echoes of it if you know what to look for. SH-9 is the most extreme example: everything west of Chickasha that is SH-9 has always been SH-9, more or less. SH-14 was once a major border-to-border route, but US 183 stole its thunder, and now it's just an alternate way of getting from Waynoka to Alva.

Beyond glimpses of the 1924 system, there seems to be little rhyme or reason as to how route numbers are assigned. Above 167 or so, there are large gaps between the numbers. Partially this has to do with derivative numbering (325 after NM 325, 209 after the similar nearby 109, 266 after 66, etc), but some of the numbers make no damn sense at all. Short spurs and connectors are generally numbered with letter suffixes, somewhat like New York; SH-54A connects SH-54 to Corn, for instance. Except when they don't--there are plenty spur routes that don't bear a letter suffix, like SH-42 to Dill City and SH-96 to the middle of nowhere. And there's 251A, when there's never been a 251...

[WillWeaverRVA]

While Henrico County has not ever had VDOT-maintained secondary roads, for years they had inventory numbers that mimicked the SR-numbering system.  Official maps in the 50s-60s showed them and the 1958 Henrico County map shows all of them.  There was no SR 895 in 1958 there either.

I need to find the 1958 Henrico County map, then, I could use it for a project I've had in mind for a while...

Thanks for clearing all that up for me, though.

[agentsteel53]

The reason for this is that until Caltrans adopted the FHWA manual with a supplement in 2004, the Caltrans Traffic Manual restricted the use of "TO" tabs to signing the way to a freeway.  This restriction no longer exists but I am not personally aware of any field examples of "TO" being used otherwise than to lead to a freeway.

There are some "TO 178" trailblazers in Bakersfield that refer to the surface street between the freeway 178 and the 99 freeway.  I do not recall seeing them more recently than about a year ago, so they must qualify under the new rule. 

there was until the early 90s a "TO 49" somewhere in the Sierras that was notable for being a white spade.  I have no idea where; I never saw it.

[RustyK]

Washington runs on very strict system where  two digit east-west state routes run south to north in two columns and two digit north-south run west to east in increasing  intervals. Three digit routes use a branch numbering scheme, so routes off SR 27 are SR 27x. Routes off interstate 5 are SR 5xx, usually increasing south to north or west to east, routes off US-12 are 12x

I go back and forth on my feelings with Washington's system.  I'm preferable to the Interstate scheme - 1xx, 2xx, etc, but I know you can't do that for the silly number of routes that start off of 5 or 90.  I do like the odd quirk that 522, the roadway that basically connects I-5 to US 2, is "5 to 2".  With some numbers, I haven't been able to find their origins yet - like 202.  20 is too far north, so it either continued north to 2 once upon a time or it's just a random occurance.  If you defined the number as branching from the most major route at an endpoint, it should be 902, shoudn't it?  Even if it was put into place when US 10 went through, it'd be 102 -- although something off of US 101 might have that number anyway (I don't recall off-hand).

[agentsteel53]

although something off of US 101 might have that number anyway (I don't recall off-hand).

you are correct.  101's children start at 102 and go at least as high as 113 and I am sure quite farther.

I believe the renumbering was in 1964 and took into account the new interstates, as opposed to the older US routes, which is why US-10 and US-99 did not get any children: they all were assigned to I-90 and I-5.  Even I-82 has some children, like 821, which is an old US-97 alignment. 

[TheStranger]

There are some "TO 178" trailblazers in Bakersfield that refer to the surface street between the freeway 178 and the 99 freeway.  I do not recall seeing them more recently than about a year ago, so they must qualify under the new rule. 

Isn't that surface street actually Route 178 (and not part of a gap)?  In which case, "TO" isn't being used correctly here either.

I did recall another Sacramento example: "To I-80 West" along westbound US 50 around Stockton Boulevard.  Of course, just like westbound I-80 being signed for "US 101" (as opposed to the correct "TO US 101")  on its last few miles in SF, the latest signage for the through lanes of westbound US 50/Business 80 at I-5 is "I-80 West San Francisco," even though that route is not at all I-80 (still another 4 miles away from that spot).

In another thread, I recall mentioning that the signage for southbound 101 around the East Los Angeles Interchange fits the new rule, basically "US 101 TO I-5/I-10."

[agentsteel53]

Isn't that surface street actually Route 178 (and not part of a gap)?  In which case, "TO" isn't being used correctly here either.

the signs are on a road that is not 178, while the surface street is signed correctly as 178.  They are trailblazers in the truest sense of the word.  The reason I say they point to the surface street and not the freeway, is because, heading west on this road (I forget which one, some arterial coming from Union St - old US99 - just south of 178) the trailblazers say "to west 178".

[TheStranger]

Isn't that surface street actually Route 178 (and not part of a gap)?  In which case, "TO" isn't being used correctly here either.

the signs are on a road that is not 178, while the surface street is signed correctly as 178.  They are trailblazers in the truest sense of the word.  The reason I say they point to the surface street and not the freeway, is because, heading west on this road (I forget which one, some arterial coming from Union St - old US99 - just south of 178) the trailblazers say "to west 178".

Thanks for the clarification.  Just looking at a map, that would be 24th Street between old 99/current 204 (Golden State Avenue) and Route 178 at M Street, right?

[Brandon]

Rich Carlson did most of the original leg work for this and deserves the credit for listing how Illinois routes are numbered.
http://n9jig.com/

Illinois started numbering routes in order as State Bond Issue (SBI) Routes in 1918.  They were numbered from 1 to 46 in the first batch, and then from 47 to 185 in the second batch in 1924.  Many of these original SBI Routes still carry their original number.  The SBI Route numbers are still used, even when superseeded by an US route number i.e. US-20 is still known by IDOT as SBI Route 5.  There are also other designations that generally aren't seen by the public.  Here are some of them:
FAI - Federal Aid Interstate such as I-55 or I-80 are known as FAI-55 or FAI-80.
FAP - Federal Aid Primary.  Usually used in the planning stages such as FAP-431 for what is now I-355, and FAP-432 for the proposed northern extension of IL-53.
FAS - Federal Aid Secondary.  Similar to the FAP Routes.
HB - House Bill.  Route authorized by a House Bill.
SB - Senate Bill.  Likewise by the Senate.
OR - Other Route.  Funded by a different mechanism.

There is not a numbering pattern, but some 3dil routes are bunched together.  Then there's a few that simply sounded good such as IL-38 for what was US-30A.  Sound it out and you'll see.

[RustyK]

although something off of US 101 might have that number anyway (I don't recall off-hand).

you are correct.  101's children start at 102 and go at least as high as 113 and I am sure quite farther.

I believe the renumbering was in 1964 and took into account the new interstates, as opposed to the older US routes, which is why US-10 and US-99 did not get any children: they all were assigned to I-90 and I-5.  Even I-82 has some children, like 821, which is an old US-97 alignment. 

Interesting.  Why was 202 given that number, then?  Did it originally get all the way up to US 2?  I can't imagine how, unless it followed SR 9's alignment, or went up 522's alignment... Or does it somehow justify the number because it meets 203?

[corco]

Interesting.  Why was 202 given that number, then?  Did it originally get all the way up to US 2?  I can't imagine how, unless it followed SR 9's alignment, or went up 522's alignment... Or does it somehow justify the number because it meets 203?

202 used to follow the route of 522 up to Monroe, but that was switched sometime in the 70s to give the Monroe-Seattle corridor one number.

There are a few other oddities in Washington, like SR 92 and 96 are "3 digit" branches of SR 9, since "90X" is taken by I-90.
SR 121 doesn't connect at all to US-12, but used to before being truncated.
SR 193 was supposed to one day connect to US-195, but the road was never built.
Some routes off of US-97 consider 97 to be "SR 15" despite that never existing (so a 15X and a 97X are both US-97 child routes)
Same with US-395- considered to be "SR 29" despite that never existing (so 29X and 39X are both US-395)
On that note, SR 290 no longer connects to US-395.
SR 181 doesn't connect with SR 18 anymore, but it used to.
Because US-2 gets 20X routes, SR 20 gets saddled with 21X, and SR 21 doesn't have any child routes.
SRs 224 and 225 don't connect to SR 22 and never have
SRs 432 and 433 are remnant numbers and used to be 832 and 833, but for conveniences sake they didn't assign a more logical number when they changed them

you are correct.  101's children start at 102 and go at least as high as 113 and I am sure quite farther.

All the way to 119- and since all the numbers have been used at some point between 100 and 119, SR 19 was commissioned as a child route of US-101 that doesn't fit the grid at all.

[corco]

Wyoming has three separate systems for state numbering.

For most routes, these being the minor routes, the numbers are issued by county in alphabetical order so
Albany: 10-29 (highest route assigned is 14)
Big Horn: 30-49  (37)
Campbell: 50-69 (51, or 59 depending on if you consider that to be a minor route- which I would disagree with)
Carbon: 70-89 (78)
Converse: 90-109 (96)
Crook: 110-129 (113, or 116 if you consider that to be a minor route- which I would disagree with)
Fremont: 130-149 (139)
Goshen: 150-169 (161)
Hot Springs: 170-189 (175)
Johnson: 190-209 (196)
Laramie: 210-229 (225)
Lincoln: 230-249 (241)
Natrona: 250-269 (259)
Niobrara: 270-289 (273)
Park: 290-309 (296)
Platte: 310-329 (321)
Sheridan: 330-349 (345)
Sublette: 350-369 (354)
Sweetwater: 370-389 (377)
Teton: 390-409 (391)
Uinta: 410-429 (414)
Washakie: 430-449 (436)
Weston: 450-469 (451)


The other system involves a bunch of more important regional routes that have numbers that branch off of the US highways. These would include 89, 114, 116, 120, 130, 230, 387, 430, 487, 530, 585, 789.

Finally, there's a third system that seems random of non-US route branches of regional importance (except for 28 and 34, all connect to another state's state highway system). These would be 22. 24, 28, 34, 59, 92, 150.

For the routes in the non-county schemes, even numbers are always east-west and odds are always north-south, so highways like 120 that are predominately straight north-south receive an east-west designation. Routes with the county scheme rarely have directionals affixed. County-numbered routes rarely connect to primary routes in another state (several go into Montana but receive secondary designations in Montana)- the exceptions being 414 which turns into Utah 43 and 151 which turns into Nebraska 88. Wyoming 239 almost connects to Idaho 34, but not quite.

Several county-numbered routes dead end at the state line and are continue into the new state as county roads. 430 is the only primary route that does this, turning into a gravel county road at the Colorado state line.

[xonhulu]

you are correct.  101's children start at 102 and go at least as high as 113 and I am sure quite farther.

There is a WA 100 which is also a child of 101.

I believe the renumbering was in 1964 and took into account the new interstates, as opposed to the older US routes, which is why US-10 and US-99 did not get any children: they all were assigned to I-90 and I-5.  Even I-82 has some children, like 821, which is an old US-97 alignment. 

I did like, in the older routes, that the US highways whose numbers were too big to fit the grid got surrogate WA route numbers for their offspring.  Thus, the routes off US 97 were "15x" and those off 395 were "29x."  More recent secondary routes use the actual number, so we now have 970 and 971 off 97, and 397 off 395.

Other goofiness: WA 131 off US 12, when 126 was available, the previously mentioned 19, and WA 92.