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State Highway Numbering Patterns

Started by Zeffy, September 07, 2014, 11:31:34 PM

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Zeffy

Is there any giant resource available that details how the highways in the 50 states came to be as they are? For example, I know NJ's history of the original routes, the 1927 renumbering, and the 1957(?) renumbering which made the routes as they are today. However, I haven't really seen how states lay out their state highways. I would assume there is some sort of grid or whatnot they follow, but I've been looking at various states and I cannot seem to find the pattern for how they are numbered. The ones out there that interest me right now are Connecticut, New York, Pennsylvania and Massachusetts, but it would be nice to have every state's highway numbering patterns.

Apologies if this has been posted before, but I didn't really see a topic like this so yeah.
Life would be boring if we didn't take an offramp every once in a while

A weird combination of a weather geek, roadgeek, car enthusiast and furry mixed with many anxiety related disorders


Laura

Maryland: http://mdroads.com/routes/md.html

QuoteThe State Roads Commission (predecessor of the current SHA) came into being on April 30, 1908. Maryland began numbering primary routes at least as far back as 1927. Although early maps do not show numbering, it is possible for numbering to have been in use at least internally many years prior. This initial state numbering appears to have come after the first US highways in 1926, as these route numbers weren't assigned elsewhere to necessitate a state number change.

QuoteThe low numbers from 2-37 were spread statewide, connecting county seats not otherwise served by a US route. The first objective of the state road system was to be able to travel from one county seat to another 'without breaking a spring.' These numbers run in the still familiar pattern - 2 through 6 through Southern Maryland, 12-21 running up the Eastern Shore (swap 33 for 17 and this shows even more), and finally 22-39 running west starting with 22 in Harford County down to 28 in Montgomery County, then west to Frederick with 33 (now 17), on to Garrett County with 37 (now US 219).

The numbers from 38 up to about 380 were the next set, and these were tightly clustered by county or region with few exceptions as follows. Most of these routes remain intact; Maryland has not had a major renumbering like some other states. Some routes run through adjacent parts of a neighboring county, but near to other routes in the cluster.

Maryland's Route Numbering System 1933:

38-42: Garrett
45-52: Allegany
53-68: Washington
69-81: Frederick
83-93: Carroll
94-106: Howard
107-124: Montgomery (Northern)
125-151: Baltimore
152-165: Harford
166-181: Anne Arundel (Northern)
182-196: Montgomery (Southern)
197-221: Prince George's
223-233: Charles
234-252: St. Mary's
253-259: Anne Arundel (Southern)
260-266: Calvert
267-286: Cecil
287-299: Kent
300-309: Queen Anne's
310-319: Caroline
320-327: (state facilities)
328-334: Talbot
335-343: Dorchester
344-355: Wicomico
356-364: Somerset
365-379: Worcester

System Additions
Above 380, few routes are clustered as those below, most notably numbers in the low 500s in Calvert County and the 440s in Kent County. Routes 313 and 404 were around from the beginning, 313 being a possible alternate for US 213, and 404 extending all the way west to Kent Island. Before the exchange program of the fifties, many seemingly minor connecting roads were numbered. Of these, quite a few were merely stubs and/or noncontiguous, with transitions between state and county maintenance; the number only applied to the state sections. By 1940, the highest number was 684. With the transportation needs of World War II came new routes, increasing the highest number into the 700s. Even today, many of the 700-718 numbers appear near military installations or critical war suppliers. In the old days, Maryland almost never ran concurrent route numbers on one road, even for a few feet. If two roads met another road slightly staggered (e.g. 137 and 138 meeting 45 in Hereford), they got different numbers, even if the separation was a city block or less! Many of these routes were later consolidated into one number or the other as this rule was relaxed.

oscar

#2
Alaska has no obvious pattern for its dozen numbered routes.

Hawaii clusters its non-Interstate routes by island, with the first digit indicating which island (for example, all 4xx routes are on Lanai or Molokai).  1-10 were reserved for Interstates and an ancient planned auto ferry system. primary routes get 2-digit numbers, secondaries 3 digits, others 4 digits.  Lots of parent-daughter numbering of related routes.  4-digit number assignments seem the most random, but they all follow the general rules on clustering by island and sometimes on numbering of related routes.  A vary logical system, completely ignored by residents who (like Alaskans) think of route numbering as a mainland/lower-48 thing.  See the FAQs section of www.hawaiihighways.com for more info.
my Hot Springs and Highways pages, with links to my roads sites:
http://www.alaskaroads.com/home.html

hotdogPi

Massachusetts and New Hampshire have more numbers in the low 100s than low numbers.

The lower numbers go through several states (MA 8, NH 9, MA 10, NH 11, MA 12, NH 25, NH 26, and MA 32 go through at least 3 states each). These are usually north-south for evens and east-west for odds (26 is diagonal). The lowest single-state route in New Hampshire is 33.

Routes numbered 60 to 97 usually have more turns than those in the low 100s, since the low 100s were created earlier (but not as early as the 8, 9, etc. mentioned earlier).

Massachusetts numbers above 200 are related to their number minus 200 in some way (for example, 203 and 3). The exception is that 213 is related to 113, not 13.
Clinched, minus I-93 (I'm missing a few miles and my file is incorrect)

Traveled, plus US 13, 44, and 50, and several state routes

I will be in Burlington VT for the eclipse.

froggie


txstateends

Quote from: Zeffy on September 07, 2014, 11:31:34 PM
Is there any giant resource available that details how the highways in the 50 states came to be as they are? so yeah.

Other than this forum (and the list of link resources it has now), I've not seen any single-compendium, be-all-end-all about it.
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SD Mapman

Quote from: txstateends on September 08, 2014, 10:00:17 AM
Quote from: Zeffy on September 07, 2014, 11:31:34 PM
Is there any giant resource available that details how the highways in the 50 states came to be as they are? so yeah.
Other than this forum (and the list of link resources it has now), I've not seen any single-compendium, be-all-end-all about it.
Yeah, this
Quote from: froggie on September 08, 2014, 05:53:55 AM
Zeffy:  here's a thread from last year on the subject.
is the best I've ever found. Maybe he should publish that.
The traveler sees what he sees, the tourist sees what he has come to see. - G.K. Chesterton

hbelkins

Kentucky generally follows the system that the US routes do for one- and two-digit routes: Odd numbers run north-south, even numbers run east-west, and the low numbers are in the north and east and the high numbers are in the south and west. There are exceptions, such as KY 26 that runs north-south and is in the southern part of the state.

West Virginia doesn't really have a systematic pattern, but in general odd numbers run east-west and even numbers run north-south.


Government would be tolerable if not for politicians and bureaucrats.

jp the roadgeek

The CT system is hard to explain.  Most of the low numbers are assigned to the US route system (1,5,6,7), or to the old New England Interstate system (8,10,12,32).  Many are numbered to be reciprocal with other states if they cross the border.  I do see somewhat of a pattern for odd numbers over 70 when you get east of New Haven, and they get higher as you move west to east (77,79,81,83,85,87,89,97), and a lot of consecutive route numbers are set up in clusters (30's and 50's in Fairfield County), 60's and low 70's in greater Waterbury. 140's and 150's in New Haven and Middlesex county, 160's-180's in Hartford county.  Only a couple (244, 372) are renumbers of the original routing of the associated 2 digit route.
Interstates I've clinched: 97, 290 (MA), 291 (CT), 291 (MA), 293, 295 (DE-NJ-PA), 295 (RI-MA), 384, 391, 395 (CT-MA), 395 (MD), 495 (DE), 610 (LA), 684, 691, 695 (MD), 695 (NY), 795 (MD)

J N Winkler

Besides NE2's thread, does anyone have an Archive.org link to J.P. Kirby's page (now long gone from the active Internet, I am sure) cataloguing numbering patterns?
"It is necessary to spend a hundred lire now to save a thousand lire later."--Piero Puricelli, explaining the need for a first-class road system to Benito Mussolini

TEG24601

#10

For Washington, from Wikipedia, partially written by me.

QuoteMost state routes are numbered in a grid, with even-numbered routes running east—west and odd-numbered routes running north—south. Even two-digit routes increase from south to north in three "strips", with SR 4, SR 6, and SR 8 in the western part of the state, SR 14, SR 16, SR 18, and SR 20 along the Interstate 5 corridor, and SR 22, SR 24, SR 26, SR 28, and former SR 30 in the east. Odd numbers similarly increase from west to east, with SR 3, Interstate 5, SR 7, SR 9, SR 11, SR 17, SR 21, SR 23, SR 25, SR 27, and SR 31 following this general progression. (SR 19 was added in 1991, and lies west of SR 3; SR 35 and SR 41 are extensions of highways in adjacent states.) Three-digit routes (and SR 92 and SR 96) are usually numbered by taking the first one or two digits of a route it connects to and adding another digit or two. In some cases, instead of using the two-digit route's actual number, a number that would fit the grid is used instead.

Add to this, that in general, the 3-digit State Routes, increment from South to North and West to East.  And that US 101 is treated as SR 1.
They said take a left at the fork in the road.  I didn't think they literally meant a fork, until plain as day, there was a fork sticking out of the road at a junction.

Zeffy

Quote from: froggie on September 08, 2014, 05:53:55 AM
Zeffy:  here's a thread from last year on the subject.

There we go, I vaguely remembered something like that but also couldn't find it (I also forgot I posted in the thread as well!) in a forum search. Thanks for that!
Life would be boring if we didn't take an offramp every once in a while

A weird combination of a weather geek, roadgeek, car enthusiast and furry mixed with many anxiety related disorders

txstateends

((apologies if some of this is long-ish, the TxDOT way isn't easily put into 1 or 2 sentences   ;-)  ))

As for Texas (without scouring Wikipedia or TxDOT or some other site-flavor-of-the-moment, which might do more to complicate things), basically there is no set numbering pattern. 

Primary state routes
* have 1, 2, or 3 digit numbers basically anywhere in the state
* no odds-over-here/evens-over-there, or smaller-numbers-here/larger-numbers-there type of setup
* no US-style parent-child numbering or Interstate-style 2di or 3di branching
* no orderly statewide grid-shaped pattern
* despite seeing something in the past say to the effect that primary state routes are assigned in order, that hasn't always been the case (if it ever really was)
* most primary routes have termini at other numbered roads (Interstates, US, other TX primary routes) but there are exceptions
* usually there's no primary route with a number that is the same as a number of a route that crosses the primary route along its way
* occasionally, a primary route can be discontinuous
* can also have one or more business routes, which usually can be found along the original or former route of a primary state route through a town 

Secondary state routes
* basically made up of Farm-to-Market and Ranch-to-Market roads
* have 1, 2, 3, or 4 digit numbers
* are of the same non-pattern as primary state routes' make-up above
* a divider of sorts has been referred to in the past between where the FMs are and where the RMs are in the state, but that's not a steadfast-brick-wall thing; there are more FMs in the east and more RMs in the west, but the opposite can be found in several places
* no FM and RM share the same route number (you won't find an FM 10 and an RM 10, for example)
* most FMs and RMs have their termini at another numbered road, like primary routes, but there are several exceptions scattered around the state: some FMs/RMs have one terminus not at another numbered road, but at a county road intersection or continue as a county road; while others have both termini that don't involve another numbered road (those do cross at least one other numbered road in-between)
* a few routes tried to convert to so-called 'urban roads' on a somewhat-tangible basis several years ago (due to many of the secondary roads being in urbanized and growing areas), but were largely unpopular when plans for conversion were released...in TxDOT's records, the URs do exist, but actual on-the-road signage still shows them as their original FM or RM route...the URs didn't change numbering upon conversion in TxDOT's system from the previous FM or RM version, either
* usually there's no secondary route with a number that is the same as a number of a route that crosses the secondary route along its way
* a discontinous FM/RM is very rare
* a business route of an FM/RM is very rare as well

Other state routes:
Loops have a mainly 1, 2, or 3 digit number (the 4-digit Loop 1604 around San Antonio is the major exception) and as with primary and secondary routes, have no real numbering pattern.  They can be found anywhere in the state.  Usually there's no loop route with a number that is the same as a number of a route that crosses the loop route along its way.

Spurs are numbered similarly to loops; 1, 2, or 3 digit numbering, no pattern, anywhere in the state.  This applies to regular spurs only.  Another set of spurs are actual adjuncts, but only from a few scattered FMs or RMs.  The FM/RM spurs are numbered like their main FM/RM route numbers (1, 2, 3, or 4 digit), but aren't signed with a SPUR banner over a FM/RM shield, but use spur shields like regular spurs do.

Park roads/Recreational roads, which are found in or leading to park or recreational areas around the state, have no pattern of numbering.  Either one can be found with 1, 2, or 3 digits.  They are numbered separately from the other types of state routes.  Park roads for the most part take over the function of a numbered road from an approaching US or other state route once the road enters the confines of a state park; otherwise, either type road can connect a numbered road to a nearby park or recreational area.

As for lettered roads, none have been used in TX before, with the exception of OSR within the primary set of routes.  Both its termini are along TX 21 and span an historic stretch of the Old San Antonio Road, hence the initials for the route.

County roads are not signed at the same level as TxDOT's numbered state roads, but are labeled on the county level with either individual blue-yellow pentagons or with varying types of street blades, while TxDOT indicates them with varying sizes of LGSes as a guiding tool rather than on a shield/numbering type of basis.  As for numbering, it varies by county.  Some have solely numbers, others are a mixture of number/letter characters for labeling.  Most counties use anywhere from 1 to 5 digits; 3 or 4 are the arrangement of digits usually found on many county road signs.  Numbering placement varies, but many use a system based on where precincts are in the county (There are 4 precincts in each county, based on local population count).
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dgolub

New York generally uses two-digit numbers for longer routes and three-digit number for shorter routes within a particular area of the state.  Certain regions have three-digit numbers in a particular range.  For example, Long Island originally had everything from NY 101 to NY 115, although three of those were decommissioned:

NY 103 - Atlantic Avenue
NY 104 - Rockaway Boulevard and Rockaway Turnpike (currently Nassau CR 257)
NY 113 - Quogue-Riverhead Road (currently Suffolk CR 104)
NY 115 - Wantagh Avenue (currently Nassau CR 189)

It's likely that Westchester once had everything from NY 116 to NY 141.  It's known that Mamaroneck Avenue was once NY 126, but I can't say for certain about the other missing numbers.  Routes that don't fit in the range (e.g. NY 135, NY 347, and NY 454 on Long Island) are in many cases roads that were constructed at a later date and got assigned some number that was not already taken--or some number that had been decommissioned elsewhere, as in the case of the current NY 113 and NY 115 in Poughkeepsie.

dfwmapper

Quote from: txstateends on September 08, 2014, 07:15:15 PM
* a few routes tried to convert to so-called 'urban roads' on a somewhat-tangible basis several years ago (due to many of the secondary roads being in urbanized and growing areas), but were largely unpopular when plans for conversion were released...in TxDOT's records, the URs do exist, but actual on-the-road signage still shows them as their original FM or RM route...the URs didn't change numbering upon conversion in TxDOT's system from the previous FM or RM version, either
Urban roads were so designated because that makes them ineligible for state funding for widening of the road. Maintenance only. Essentially a sneaky way to dump responsibility on the city/county without having to get them to agree to it first.
QuoteLoops have a mainly 1, 2, or 3 digit number (the 4-digit Loop 1604 around San Antonio is the major exception) and as with primary and secondary routes, have no real numbering pattern.  They can be found anywhere in the state.  Usually there's no loop route with a number that is the same as a number of a route that crosses the loop route along its way.
1604 being the exception because it was originally FM 1604 running between US 87 (I-10 west) and US 281, and was extended piece by piece to create a complete loop, then renamed as a loop.

vdeane

#15
Quote from: dgolub on September 08, 2014, 07:56:10 PM
New York generally uses two-digit numbers for longer routes and three-digit number for shorter routes within a particular area of the state.  Certain regions have three-digit numbers in a particular range.  For example, Long Island originally had everything from NY 101 to NY 115, although three of those were decommissioned:

NY 103 - Atlantic Avenue
NY 104 - Rockaway Boulevard and Rockaway Turnpike (currently Nassau CR 257)
NY 113 - Quogue-Riverhead Road (currently Suffolk CR 104)
NY 115 - Wantagh Avenue (currently Nassau CR 189)

It's likely that Westchester once had everything from NY 116 to NY 141.  It's known that Mamaroneck Avenue was once NY 126, but I can't say for certain about the other missing numbers.  Routes that don't fit in the range (e.g. NY 135, NY 347, and NY 454 on Long Island) are in many cases roads that were constructed at a later date and got assigned some number that was not already taken--or some number that had been decommissioned elsewhere, as in the case of the current NY 113 and NY 115 in Poughkeepsie.
I believe NY adopted a system where 2dny routes would be primary routes across the state (even N-S, odd E-W) with 3dny routes being more minor ones assigned by a clustering system.  Of course, there are about a billion exceptions, and it's been ignored since the initial numbering in the early 30s.  Before then, there was a small system of 2dny routes in the late 20s that went by the wayside when the US highways were designated.  Yep, NY established a system only to have to scrap it a couple years later when the US highways came in.  That might be why NY has never cared much for US routes and didn't care to renumber anything other than NY 87 (to NY 812) for the interstates.

EDIT: http://en.wikipedia.org/wiki/1930_state_highway_renumbering_(New_York)
Please note: All comments here represent my own personal opinion and do not reflect the official position of NYSDOT or its affiliates.

WashuOtaku

When North Carolina first started their state number system, it was very uniformed.  But after a decade or two they said "f*ck it, let's make meth," which is what we have today.   :sombrero:

dgolub

Quote from: vdeane on September 09, 2014, 01:16:53 PM
Quote from: dgolub on September 08, 2014, 07:56:10 PM
New York generally uses two-digit numbers for longer routes and three-digit number for shorter routes within a particular area of the state.  Certain regions have three-digit numbers in a particular range.  For example, Long Island originally had everything from NY 101 to NY 115, although three of those were decommissioned:

NY 103 - Atlantic Avenue
NY 104 - Rockaway Boulevard and Rockaway Turnpike (currently Nassau CR 257)
NY 113 - Quogue-Riverhead Road (currently Suffolk CR 104)
NY 115 - Wantagh Avenue (currently Nassau CR 189)

It's likely that Westchester once had everything from NY 116 to NY 141.  It's known that Mamaroneck Avenue was once NY 126, but I can't say for certain about the other missing numbers.  Routes that don't fit in the range (e.g. NY 135, NY 347, and NY 454 on Long Island) are in many cases roads that were constructed at a later date and got assigned some number that was not already taken--or some number that had been decommissioned elsewhere, as in the case of the current NY 113 and NY 115 in Poughkeepsie.
I believe NY adopted a system where 2dny routes would be primary routes across the state (even N-S, odd E-W) with 3dny routes being more minor ones assigned by a clustering system.  Of course, there are about a billion exceptions, and it's been ignored since the initial numbering in the early 30s.  Before then, there was a small system of 2dny routes in the late 20s that went by the wayside when the US highways were designated.  Yep, NY established a system only to have to scrap it a couple years later when the US highways came in.  That might be why NY has never cared much for US routes and didn't care to renumber anything other than NY 87 (to NY 812) for the interstates.

EDIT: http://en.wikipedia.org/wiki/1930_state_highway_renumbering_(New_York)

The thing is that there aren't too many cases (if any) where the interstate and state route with the same number are at all near each other, except in cases where one turns into the other like I-787 and NY 787.  For example, there's I-295 and NY 295, but they're more than 100 miles apart so it's unlikely that anyone would confuse them.

Now, when it comes to county routes, that's a whole other story.  People taking the Long Island Expressway (I-495) out to Montauk regularly get off at NY 111 when they really want Suffolk CR 111.  And then there's Nassau, which doesn't pose a problem because the county route are all unsigned.  However, they've got CR 25, CR 27, and CR 110 that run right next to NY 25, NY 27, and NY 110, respectively.  If Nassau were to start signing county routes, those three would have to get renumbered to avoid confusing people.

roadman65

FL pretty much uses the Federal system for US routes on its one and two digit routes.

However, on its three digits certain numbers are assigned to a specific region.  Like NE 2 once said it was intended for an obvious purpose when first implemented, but got messed up later with expansion of the state's road network.

Double 00 routes tend to be long distance routes that diagonally cross the Florida Peninsula with many of them are silent like SR 400, 500, 600, and 700. FL  200, though is signed, but most of it is unsigned where concurrent with US 301 from Ocala to Callahan.  FL 100 is signed for several miles across the state, but there is a section from Lake City to the GA Line that is not.
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

jbnv

Don't bother asking about Louisiana. There is evidence of loose patterning, but the idea of conformity vanished when major routes got 3xxx numbers.  :rolleyes:
🆕 Louisiana Highways on Twitter | Yes, I like Clearview. Deal with it. | Redos: US | La. | Route Challenge

vdeane

Quote from: dgolub on September 13, 2014, 09:58:49 AM
Quote from: vdeane on September 09, 2014, 01:16:53 PM
Quote from: dgolub on September 08, 2014, 07:56:10 PM
New York generally uses two-digit numbers for longer routes and three-digit number for shorter routes within a particular area of the state.  Certain regions have three-digit numbers in a particular range.  For example, Long Island originally had everything from NY 101 to NY 115, although three of those were decommissioned:

NY 103 - Atlantic Avenue
NY 104 - Rockaway Boulevard and Rockaway Turnpike (currently Nassau CR 257)
NY 113 - Quogue-Riverhead Road (currently Suffolk CR 104)
NY 115 - Wantagh Avenue (currently Nassau CR 189)

It's likely that Westchester once had everything from NY 116 to NY 141.  It's known that Mamaroneck Avenue was once NY 126, but I can't say for certain about the other missing numbers.  Routes that don't fit in the range (e.g. NY 135, NY 347, and NY 454 on Long Island) are in many cases roads that were constructed at a later date and got assigned some number that was not already taken--or some number that had been decommissioned elsewhere, as in the case of the current NY 113 and NY 115 in Poughkeepsie.
I believe NY adopted a system where 2dny routes would be primary routes across the state (even N-S, odd E-W) with 3dny routes being more minor ones assigned by a clustering system.  Of course, there are about a billion exceptions, and it's been ignored since the initial numbering in the early 30s.  Before then, there was a small system of 2dny routes in the late 20s that went by the wayside when the US highways were designated.  Yep, NY established a system only to have to scrap it a couple years later when the US highways came in.  That might be why NY has never cared much for US routes and didn't care to renumber anything other than NY 87 (to NY 812) for the interstates.

EDIT: http://en.wikipedia.org/wiki/1930_state_highway_renumbering_(New_York)

The thing is that there aren't too many cases (if any) where the interstate and state route with the same number are at all near each other, except in cases where one turns into the other like I-787 and NY 787.  For example, there's I-295 and NY 295, but they're more than 100 miles apart so it's unlikely that anyone would confuse them.

Now, when it comes to county routes, that's a whole other story.  People taking the Long Island Expressway (I-495) out to Montauk regularly get off at NY 111 when they really want Suffolk CR 111.  And then there's Nassau, which doesn't pose a problem because the county route are all unsigned.  However, they've got CR 25, CR 27, and CR 110 that run right next to NY 25, NY 27, and NY 110, respectively.  If Nassau were to start signing county routes, those three would have to get renumbered to avoid confusing people.
I think I figured out the mystery of why NY 87 was renumbered but others weren't, even though NY 87 didn't go anywhere near I-87: NY 87 and I-87 would have both existed in Region 7.  Aside from extensions and the Thruway, this doesn't happen with any of the still-existing duplicates.
Please note: All comments here represent my own personal opinion and do not reflect the official position of NYSDOT or its affiliates.

Scott5114

Oklahoma is roughly sequential, but all hell broke loose after about 1940 or so, with previous numbers being recycled.
uncontrollable freak sardine salad chef

SD Mapman

I'm just going to rehash what was said last year.
Quote from: NE2 on October 12, 2013, 03:15:40 AM
South Dakota had numbered and signed its state highways by 1926 in a perfect grid. Numbers ran from 11 in the east to 85 in the west and 12 in the north to 52 in the south.
Quote from: SD Mapman on October 11, 2013, 12:23:47 AM
South Dakota:
Similar grid to the US system for 2 digits started in the 1920s. When the US system was designated, it overrode the previous state highway that just happened to be in the way (US 281 over SD 41, for instance). 3 digits started to show up in the '70s and are assigned based on a statewide street grid, e.g. 100th Avenue at the Wyoming/Montana border, increasing west-to-east, and 100th Street at the ND border increasing north-to-south. The east-west 3 digit numbering goes to the nearest even street, adding 100 if necessary. The north-south 3 digit numbering goes to the inverse of the nearest odd street (101 at the Minnesota border and so on), adding 100 if necessary. 1804 and 1806 are from 1976. They follow the Missouri River.
The traveler sees what he sees, the tourist sees what he has come to see. - G.K. Chesterton

Brandon

Illinois was done in legislative order originally.  Some of the higher, 3 digit route appear to have been clustered.
"If you think this has a happy ending, you haven't been paying attention." - Ramsay Bolton

"Symbolic of his struggle against reality." - Reg

DandyDan

I have no idea what Nebraska's system is based on.  Iowa's is based on the order in which they were approved, but since the system was created, the US Highways and the interstates came into being, and they renumbered a large number of highways in 1969, so a large number of highways do not have their original number.
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