Highways that don't follow even/odd numbering system

[golden eagle]

Even-numbered routes traditionally travel east and west, while odd-numbered routes are north and south. GA 400 bucks this trend by being signed north and south. I've also seen a portion of GA 124 be signed east/west, but later signed as north/south.

[NE2]

Georgia only followed directional parity on low numbers. (Current 4 was not part of the original system.)

[hotdogPi]

I-85 is more east-west than north-south.

Diagonal routes that could be on here, but could be signed either way, are US 52, US 62, and I-71. (And US 202, but a 3dus does not have even/odd rules like a 2dus does.)

Different systems have different even/odd rules, too.

Historically, New England routes and 3-digit routes in Massachusetts were reversed from US/Interstate routes. Most followed those rules, but there were some exceptions, even to those. New England Route 18 was east-west, and a few years later, MA 107 was north-south (the even/odd rules were reversed for those systems). VT/NH 18 and MA 107 still exist today, but there is no grid anymore, with all the new routes.

[bulldog1979]

Michigan has never really used parity to assign state highway numbers. M-66 has been a north—south highway since 1919, and M-55 has also traditionally been an east—west highway. there are plenty of other examples that buck the parity-based numbering scheme. M-69 is east—west and M-26 is mostly north—south. M-107 was always east—west, and M-108 was north—south.

[Zeffy]

NJ 18 is N/S. I-76 is called the 'North-South Freeway' in New Jersey, even though it runs primarily east-to-west.

[hotdogPi]

There is really no point to listing routes that don't follow a grid, since half of those apply, which is too many to list.

[The High Plains Traveler]

I-85 is more east-west than north-south.

Diagonal routes that could be on here, but could be signed either way, are US 52, US 62, and I-71. (And US 202, but a 3dus does not have even/odd rules like a 2dus does.)

I haven't looked at I-85, but definite parity rule breakers are U.S. 33, U.S. 79 and I-82. Pretty sure U.S. 52 will calculate as east-west, and I would guess U.S. 62 would too.

[Alps]

This topic only applies to grid numbering systems. NJ used a radial system, so they're out. Most of the Northeast actually doesn't apply - NY started out with a reverse grid, but there are so many exceptions since then that it's not worth reconstructing. Hint: get started with 8, 10, 12, 14, 22, 28 (ish), 30, 32, 34, 38. Continue with 3, 5, 7, 17, 23, 25, 27, 29, 31, 33.

[hotdogPi]

This topic only applies to grid numbering systems. NJ used a radial system, so they're out. Most of the Northeast actually doesn't apply - NY started out with a reverse grid, but there are so many exceptions since then that it's not worth reconstructing. Hint: get started with 8, 10, 12, 14, 22, 28 (ish), 30, 32, 34, 38. Continue with 3, 5, 7, 17, 23, 25, 27, 29, 31, 33.

New England uses a reverse grid for New England routes (some of 1-32 and 38) and numbers slightly higher than 100.

[TheStranger]

There is really no point to listing routes that don't follow a grid, since half of those apply, which is too many to list.

On the other hand, US 42 and I-71 represent parallel routes that take different numbering choices in respect to a grid.

---

California is nominally an even/odd state (and has been since 1934), but there have been many exceptions from 1964 onward as more routes were added to reflect state maintenance:

2 (only the Glendale Freeway portion)
37 (derived from an earlier north-south route that used much of the same corridor)
70 (only from Catlett to Route 191; former Route 24 and US 40A)
72 (former US 101)
77?
82 (former US 101)
84 (only the segment north of Rio Vista)
91 (former US 91 and pre-1964 Route 14)
former 117 (now 905)
119
124
129
137
144
151
155
158
160 (former Route 24)
161
164 (unsigned; existing portion has been part of Route 19 since 1934)
167
174
175 (includes part of former Route 29)
182
184
186
188
189
193
201
203
204 (former US 99)
former 206
217
219
223
225
236 (former Route 9)
237 (former Route 9)
238 (former Route 9 and Route 17)
242 (former Route 24)
253
254 (former US 101)
266 (continuation of NV 266)
267?
former 275 (former US 40/99W)
284
299 (former US 299)
371 (former Route 71)

[GaryV]

Michigan has never really used parity to assign state highway numbers. M-66 has been a north—south highway since 1919, and M-55 has also traditionally been an east—west highway. there are plenty of other examples that buck the parity-based numbering scheme. M-69 is east—west and M-26 is mostly north—south. M-107 was always east—west, and M-108 was north—south.

Michigan's first highway numbers were assigned in descending order of length, starting with M-10 (no single digits back nearly 100 years ago).  M-10, roughly following today's I-75 and US-23 along Lake Huron, was the longest route, followed by other N/S routes (M-11 ~ US-31, M-13 ~ US-131 and M-14 ~ US-27) in the lower peninsula and M-12 which more-or-less became US-2 in 1926.

Later numbers were added in numerical order as highways were added to the system, without regard to N/S or E/W.

[NE2]

guys
https://www.aaroads.com/forum/index.php?topic=10423

[mhh]

I-69 between Port Huron and Lansing, Michigan, runs east-west and is posted as such.

[US71]

A lot of Oklahoma highways.

[dgolub]

New York doesn't follow the odd/even convention.  For example, NY 25 and NY 27 are east/west, while NY 106, NY 108, NY 110, NY 112, and NY 114 are all north/south.

[jp the roadgeek]

Other than routes that are remnants of the New England Interstate system, I don't know of any rhyme or reason to route systems in any New England state.

[hotdogPi]

Other than routes that are remnants of the New England Interstate system, I don't know of any rhyme or reason to route systems in any New England state.

Numbers slightly above 100, for the most part, have a reverse numbering system.

[Alps]

New York doesn't follow the odd/even convention.  For example, NY 25 and NY 27 are east/west, while NY 106, NY 108, NY 110, NY 112, and NY 114 are all north/south.

NY started out with a reverse grid, but there are so many exceptions since then that it's not worth reconstructing. Hint: get started with 8, 10, 12, 14, 22, 28 (ish), 30, 32, 34, 38. Continue with 3, 5, 7, 17, 23, 25, 27, 29, 31, 33.

guys
https://www.aaroads.com/forum/index.php?topic=10423

[bzakharin]

US 9 in Delaware is East-West. It's North-South in NJ and NY.

[CentralCAroadgeek]

There is really no point to listing routes that don't follow a grid, since half of those apply, which is too many to list.

On the other hand, US 42 and I-71 represent parallel routes that take different numbering choices in respect to a grid.

---

California is nominally an even/odd state (and has been since 1934), but there have been many exceptions from 1964 onward as more routes were added to reflect state maintenance:

2 (only the Glendale Freeway portion)
37 (derived from an earlier north-south route that used much of the same corridor)
70 (only from Catlett to Route 191; former Route 24 and US 40A)
72 (former US 101)
77?
82 (former US 101)
84 (only the segment north of Rio Vista)
91 (former US 91 and pre-1964 Route 14)
former 117 (now 905)
119
124
129
137
144
151
155
158
160 (former Route 24)
161
164 (unsigned; existing portion has been part of Route 19 since 1934)
167
174
175 (includes part of former Route 29)
182
184
186
188
189
193
201
203
204 (former US 99)
former 206
217
219
223
225
236 (former Route 9)
237 (former Route 9)
238 (former Route 9 and Route 17)
242 (former Route 24)
253
254 (former US 101)
266 (continuation of NV 266)
267?
former 275 (former US 40/99W)
284
299 (former US 299)
371 (former Route 71)

You forgot CA-14.

[NE2]

There is really no point to listing routes that don't follow a grid, since half of those apply, which is too many to list.

On the other hand, US 42 and I-71 represent parallel routes that take different numbering choices in respect to a grid.

---

California is nominally an even/odd state (and has been since 1934), but there have been many exceptions from 1964 onward as more routes were added to reflect state maintenance:

2 (only the Glendale Freeway portion)
37 (derived from an earlier north-south route that used much of the same corridor)
70 (only from Catlett to Route 191; former Route 24 and US 40A)
72 (former US 101)
77?
82 (former US 101)
84 (only the segment north of Rio Vista)
91 (former US 91 and pre-1964 Route 14)
former 117 (now 905)
119
124
129
137
144
151
155
158
160 (former Route 24)
161
164 (unsigned; existing portion has been part of Route 19 since 1934)
167
174
175 (includes part of former Route 29)
182
184
186
188
189
193
201
203
204 (former US 99)
former 206
217
219
223
225
236 (former Route 9)
237 (former Route 9)
238 (former Route 9 and Route 17)
242 (former Route 24)
253
254 (former US 101)
266 (continuation of NV 266)
267?
former 275 (former US 40/99W)
284
299 (former US 299)
371 (former Route 71)

You forgot CA-14.

You forgot Poland.

[tidecat]

Kentucky has so many routes in its system that anything numbered above 100 is effectively random.  There are also lots of instances where counties use groups of consecutive numbers.

The strangest pair in Louisville to me is KY 1747 (N/S) and KY 1447 (E/W), which actually do intersect each other.  KY 47 isn't in the area and doesn't interact with either route.

[hbelkins]

Kentucky has so many routes in its system that anything numbered above 100 is effectively random.  There are also lots of instances where counties use groups of consecutive numbers.

The strangest pair in Louisville to me is KY 1747 (N/S) and KY 1447 (E/W), which actually do intersect each other.  KY 47 isn't in the area and doesn't interact with either route.

I was actually at that 1747-1447 intersection this week!

For the most part, Kentucky's one- and two-digit routes have nothing to do with the three- and four-digit routes.

And most of those clustering-by-county examples come from when the state took over a number of county routes in the 70s and 80s.

As for routes not following the numbering grid, KY 82 was signed as E-W for years despite running almost due N-S. Only in the last several years has it finally been signed N-S, although there is a stray "West" sign still posted in Powell County.

[jbnv]

Kentucky has so many routes in its system that anything numbered above 100 is effectively random.  There are also lots of instances where counties use groups of consecutive numbers.

In Louisiana, adherence to the convention is rather liberal. The general pattern is evident, but there are more exceptions than I care to list at this time. I think the 3xxx band throws the rule out the window altogether. Ditto for xxxx-y routes. You also have lots of routes that bend, arc, zigzag or hug waterways, making directional classification difficult.

[SD Mapman]

Wyoming.