Explaining the California SH System

[national highway 1]

Hi, I'm just wondering how California's SH ssytem works. California has had a SH system since 1934 and was renumbered in 1964. I'm curious as to know how the highways get their numbers. Because 1 digit & 2 digit routes are scattered all over the place, so i'm not sure how it works.
E.g.
CA 1 PCH
CA 2 LA
CA 3 Nthn CA
CA 4 Bay Area
I-5
US 6
CA 7 '3ft' border crossing near Calexico
I-8
CA 9 Bay area
I-10 etc.

See what i mean? it's a whole mess.

[oscar]

Hi, I'm just wondering how California's SH ssytem works. California has had a SH system since 1934 and was renumbered in 1964. I'm curious as to know how the highways get their numbers. Because 1 digit & 2 digit routes are scattered all over the place, so i'm not sure how it works.
E.g.
CA 1 PCH
CA 2 LA
CA 3 Nthn CA
CA 4 Bay Area
I-5
US 6
CA 7 '3ft' border crossing near Calexico
I-8
CA 9 Bay area
I-10 etc.

See what i mean? it's a whole mess.

It's less of a mess if you ignore the Interstate and US routes, which go by their own systems rather than California's.

[TheStranger]

This page here - http://cahighways.org/numberng.html - has a pretty good primer on how routes are assigned.  Basically, post-1964, it's been a sequential system with some clustering, but pre-1964, it was as follows:

Two numbers would be paired up for use in one half of the state (i.e. Route 2 and 3 in 1934 - of which Route 2 remains - were in SoCal) with the following pair used in the other half (i.e. Route 4 (still extant) and Route 5 (now Route 35)), continuing on into the high 100s.

Rural routes would receive higher numbers (i.e. still-existing Route 180 and Route 120), while urban routes would receive lower numbers (Routes 2 and 3 in 1934 have segments in the Los Angeles city limits; Routes 4 and 5 from 1934 cover the Bay Area).   Lengthy routes that crossed the state would receive lower numbers (i.e. Route 1 and Route 20).

(Interestingly, Route 118 - original to that era - always had its urban segment from Pasadena westward, so this was not a hard-and-fast rule.)

Some changes were made before 1964 to reflect the Interstates arriving, notably Route 10 in Los Angeles County becoming Route 42.

In 1964, while many state routes retained their pre-existing numbers, those that conflicted with interstate numbers (Route 5, Route 15) were given new identities (Route 35 and then-Route 7 in that example).

Some examples of clustering in the 1964 system include three former routings of Route 9 (Route 236, 237, 238), and the grouping of 8x routes in the Bay Area (Route 82, 84, 85, 87).  In SoCal, several 7x routes are relatively close (71, 72, 73, 74, 75, 76, 78, 79), but 71, 74, 78 and 79 all predate the 1964 renumbering.

Very few routes have received their number based on a previous designation, which is as follows:
Route 330 (formerly Route 30)
Route 371 (formerly Route 71)
Route 242 (formerly Route 24)

While California generally follows the even/odd conventions of most states, one interesting quirk that occurred in 1964 is that north-south segments of east-west routes ended up receiving even numbers for whatever reason, particularly Route 14 (formerly US 6) and Route 160 and 70 (formerly Route 24).  Route 91 took its number from being partially a segment of former US 91, though there are several other examples of the directional non-correlation:

Routes 236, 237, 238 (north-south, east-west and north-south respectively  - as noted, part of former Route 9)
unbuilt Route 157 (was to have been east-west)
Route 77 (only built segment segment is a very short east-west route, and as planned would have started out mostly in that direction)
Route 242 (north-south, former Route 24)
Routes 201 and 137 (east-west)
Routes 72 and 82 (north-south, former US 101)
Route 129 (east-west)
Route 184 (north-south)

Routes 7 and 11 fit the current CalTrans practice of simply using the lowest available number for any new highways, after their previous routings became I-710 and I-110/Route 110 respectively.  (Which makes it interesting that Route 21 has never been reused...)

There is one mini-numbering system that does exist though, for the Orange County toll routes (former 231, current 261/241).  

[agentsteel53]

excellent writeup!  I will not attempt to explain the Legislative Route Number vs Signed Route Number distinction and instead make that shuddering noise of Sideshow Bob stepping on a rake.

several routes existed in both Norcal and Socal... 1 went all the way down to San Luis Obispo (and 3 was the original southern segment of 1, from 101 (now I-5) in Dana Point back to 101 north of LA - I forget where it connected back, but certainly south of Gaviotas, where 101 turns the corner.

7 was originally the longest route in the state - it followed, roughly, modern 395 down from Oregon, into Nevada, and then it came back as 7 where 395 comes back, took the 6-395 multiplex (now just 395) to the split at Brady, which is approximately where 395 and 14 split now.  It followed 14 (US-6) to Castaic Junction where it multiplexed briefly with US-99, and then split off at Sepulveda Blvd, which was the original Bear 7 down to where it met 101, near where 405 now meets 5. 

it was immediately truncated when US-395 was extended in 1935, and then further when US-6 was extended in 1937, but remained a significant LA-area route for many years, before it was moved onto a new freeway that was then renumbered to 405.  The number was reused for the previous 15 freeway, because I-15 needed that number.  Then it was arbitrarily renumbered I-710 in 1980, and the number 7 was not used for several years.  The number was then unceremoniously dumped onto some access route to the Mexican border that could've just as elegantly had a number like 288 with no one noticing. 

same with 11 - the original Pasadena Freeway, the first freeway in CA - now some useless Mexican access route that could've just as easily been 289.  Hosers.

[TheStranger]

7 was originally the longest route in the state - it followed, roughly, modern 395 down from Oregon, into Nevada, and then it came back as 7 where 395 comes back, took the 6-395 multiplex (now just 395) to the split at Brady, which is approximately where 395 and 14 split now.  It followed 14 (US-6) to Castaic Junction where it multiplexed briefly with US-99, and then split off at Sepulveda Blvd, which was the original Bear 7 down to where it met 101, near where 405 now meets 5.  

it was immediately truncated when US-395 was extended in 1935, and then further when US-6 was extended in 1937, but remained a significant LA-area route for many years, before it was moved onto a new freeway that was then renumbered to 405.  The number was reused for the previous 15 freeway, because I-15 needed that number.  Then it was arbitrarily renumbered I-710 in 1980, and the number 7 was not used for several years.  The number was then unceremoniously dumped onto some access route to the Mexican border that could've just as elegantly had a number like 288 with no one noticing.  

same with 11 - the original Pasadena Freeway, the first freeway in CA - now some useless Mexican access route that could've just as easily been 289.  Hosers.

I think this is where California's lack of real distinction (signage-wise) between "primary" and "seconary" route hurts - 7 and 11 would be much more useful on primary routes.  i.e. why not switch "125" and "11" in San Diego, that would make more sense, though at this point 125 has existed for about 40 years (since 67 was truncated to I-8).

(The 710 renumbering dates to 1984 if I'm not mistaken, while the 110 numbering for former Route 11 came in 1981.)

I also forgot to mention that Route 107 is the fifth route that received its number based on a former routing, as it was the mid-1930s segment of Route 7 through Inglewood before the Sepuvleda routing took precedence - the only example of this type of numbering IIRC before 1964.

Speaking of US 395, the original 1934-era Route 71 once extended further south along today's I-15 (until the early 1970s) to Temecula, and then old US 395/approximately today's I-15 and Route 163 south to San Diego.

[national highway 1]

But how about the 9x routes?
90-2 bits in LA
91-Formerly US 91
92-Bay Area
93-Unconstructed-Richmond
94-San Diego
US 95
96-NorCal
US 97
CA 98-Socal, near Calexico
99-Former US 99

[national highway 1]

And the 2x Routes?
20-N of Sacramento
21-Now I-680
22-Garden Grove Fwy,LA
23-Moorpark Fwy, LA
24-Bay Area
25-Central Valley
26-Central Valley
27-Topanga Canyon, N of LA
28-Lake Tahoe
29-Napa Valley

[national highway 1]

One last thing-When US 6 was extended into CA in 1937, why did it go south to Long Beach? If US 6 had been planned differently, I'd take it along CA 120, up CA 99, then along CA 4 to I-80 at Vallejo.

[Bickendan]

You mean to US 40 in Vallejo. If it had, US 6 would have been a more-less due east-west 2-dUS and would have been an egregious violation of the US Highway numbering grid. By ramming it south from Bishop to Long Beach, it became a diagonal route (as tenuous as it was) and could get away with being south of US 10, 20, 30, 40, 50, 60 AND 70.
(Let's not talk about US 20, 26 and 30 west of Boise, lol).

[national highway 1]

But why did it have to go south?

[TheStranger]

But how about the 9x routes?
90-2 bits in LA
91-Formerly US 91
92-Bay Area
93-Unconstructed-Richmond
94-San Diego
US 95
96-NorCal
US 97
CA 98-Socal, near Calexico
99-Former US 99

90, 92, and 93 were all assigned post-1964.  94 and 98 existed in the 1930s if I'm not mistaken, though 98 at one point was half the length it is today.

You mean to US 40 in Vallejo. If it had, US 6 would have been a more-less due east-west 2-dUS and would have been an egregious violation of the US Highway numbering grid. By ramming it south from Bishop to Long Beach, it became a diagonal route (as tenuous as it was) and could get away with being south of US 10, 20, 30, 40, 50, 60 AND 70.

But why did it have to go south?

I do know the whole route became the "Grand Army of the Republic Highway" ca. 1939, including the former Route 7/current Route 14 and former Route 11/current I-110 segments; US 6 DID assimilate several other US routes along the way that originally existed (US 32 and US 38) as well.

From my understanding of how the US highway grid works, any number not in the x0 range can be diagonal to an extreme, i.e. US 66, US 68, US 52, US 62, US 59 after it supplanted the original US 96.  (It's not a strict grid like the Interstates - explaining such oddities as US 44 and US 46 being way out of sequence.)

20-N of Sacramento
21-Now I-680
22-Garden Grove Fwy,LA
23-Moorpark Fwy, LA
24-Bay Area
25-Central Valley
26-Central Valley
27-Topanga Canyon, N of LA
28-Lake Tahoe
29-Napa Valley

22 and 23 are from the pre-1964 numbering system, as is 24 (formerly a cross-state route in NorCal) and 25 (which is NOT in the Central Valley, but in the Salinas Valley, also in NorCal).  

26 is formerly State Route 8, which of course was renumbered once I-8 came around.  27 and the original 26 (which has essentially been replaced with today's I-10 west of US 101, and I-5/former US 101 from downtown Los Angeles to Route 19) are from the pre-1964 system as well. 

Route 29 existed pre-1964, and Route 28 was created in the 1950s but seems to fit in with the every-two-numbers-per-half-of-state approach that was originally in place.

---

Just realized one omission in the "odd/even" exceptions: Route 37 in the Vallejo/Novato area, signed east-west.  This however was the result of a rerouting: pre-1964 Route 37 used to follow today's Route 121 north to the Lake Berryessa and Napa areas, while pre-1964 Route 48 continued east from Sears Point to Vallejo along what is now Route 37.

[national highway 1]

The question is, why did US 6 have to curve south to enter CA? Why did it have to go to Long Beach? Couldn't it make a more E-W routing?

[TheStranger]

ausinterkid: Considering that Route 120 west of US 6 is not an all-weather route - and that the southwest extension served downtown Los Angeles - I suspect that the route was chosen to reach the largest metropolitan area possible, with the least difficulty.  I can't say for sure.

more info:
http://www.fhwa.dot.gov/infrastructure/us6.cfm

The north-south segment corresponds to the pre-US route "Midland Trail" -
http://en.wikipedia.org/wiki/Midland_Trail

[kurumi]

In older maps, the original distribution of routes is more apparent.

In LA, the following north-south routes are found, from right to left: 7 11 15 19 35 39. And east-west routes (early) are 2 6 10 14 18 22. There are gaps of 4 because the other routes are in NoCal.

In the SF Bay area, you could find 1 5 9 17 21 (13 was intended for 17, but was protested); in northern California, mainly south to north, were 8 12 16 20 24 28 32 36 44. (40 was taken by US 40)

Where are they now? From top of head:
7 = 710
11 = 110
5 = 35 (because of I-5)
9 = 9, 236, 237, 238
21 = 680
8 = 88 (or 26?) (because of I-8, AFAIK)
28 = 128 (because of NV/CA 28?)

It's interesting, based on its size (3rd in land area, 1st in population), how few numbered routes CA has compared to other states. Look at Miami metro vs. LA for example.

[TheStranger]

Don't forget that the westernmost north-south route in SoCal was Route 3 (later US 101A, now part of the extended Route 1).

Where are they now? From top of head:
7 = 710

Actually, this would be current US 395, Route 14 (former US 6), I-405, and Route 107 (which received its number in the early 1940s as a child route, when Route 7 was moved to the Sepulveda corridor entirely).  Today's Route 7 was originally Route 15.

Pre-1964 Route 35 became I-605 when the interstate era rolled around, though that change wasn't made official until 1964.

9 = 9, 236, 237, 238

As well as 262 (which also was formerly 21, and at one point would've been part of I-680).  (Also, the original routing of 85 along Saratoga-Sunnyvale/DeAnza.)

8 = 88 (or 26?) (because of I-8, AFAIK)

26 (after that number was freed up when the pre-1964 Route 26 became part of I-10).  88 I think is a 1934-era #.

28 = 128 (because of NV/CA 28?)

This, I've been curious about for years - supposedly the original Route 28 from 1934 included today's I-505/former I-5W from Winters north, but I don't think that was ever signed in the field.  Today's Route 28/NV 28 dates back to 1953.

It's interesting, based on its size (3rd in land area, 1st in population), how few numbered routes CA has compared to other states. Look at Miami metro vs. LA for example.

Some of that probably has to do with the practice of having all signed route designations based on legislative action/decision, as opposed to letting CalTrans number routes for navigational purposes, regardless of maintenance (which is Massachusetts' policy, as one comparison).

[agentsteel53]

This, I've been curious about for years - supposedly the original Route 28 from 1934 included today's I-505/former I-5W from Winters north, but I don't think that was ever signed in the field.  Today's Route 28/NV 28 dates back to 1953.

I saw 28 labeled on the original Aug, 1934 map that was published with the first mockup of a bear shield.  Have never seen an actual bear 28, though - neither the early 1934 style, nor the larger reflectorized style that would've been around in 1953.

I have two PDFs that I can email you if you'd like.  One is the Aug 1934 article, and another is an Oct 1934 showing the first bear posted in the wild.  (A bear 1, of course.)

[agentsteel53]

The north-south segment corresponds to the pre-US route "Midland Trail" -
http://en.wikipedia.org/wiki/Midland_Trail

that is exactly your answer: it followed the Midland Trail.  In fact, US-6 is the Midland Trail starting from, I believe, Denver.  Certainly from Ely, Nevada. 

[roadfro]

This, I've been curious about for years - supposedly the original Route 28 from 1934 included today's I-505/former I-5W from Winters north, but I don't think that was ever signed in the field.  Today's Route 28/NV 28 dates back to 1953.

I saw 28 labeled on the original Aug, 1934 map that was published with the first mockup of a bear shield.  Have never seen an actual bear 28, though - neither the early 1934 style, nor the larger reflectorized style that would've been around in 1953.

I have two PDFs that I can email you if you'd like.  One is the Aug 1934 article, and another is an Oct 1934 showing the first bear posted in the wild.  (A bear 1, of course.)

On the Nevada side, the road for SR 28 is shown on Nevada's 1932 state map (albeit without a number). The road received the 28 number on the redesigned Nevada state map that was published for 1933.

[agentsteel53]

does this mean the oldest Nevada state route markers are 1933?

[TheStranger]

I saw 28 labeled on the original Aug, 1934 map that was published with the first mockup of a bear shield.  Have never seen an actual bear 28, though - neither the early 1934 style, nor the larger reflectorized style that would've been around in 1953.

I have two PDFs that I can email you if you'd like.  One is the Aug 1934 article, and another is an Oct 1934 showing the first bear posted in the wild.  (A bear 1, of course.)

I'd be more than happy to check out those PDFs!  Was there a "preliminary" map released in 1934 in the vein of the early US highway maps (the ones that showed US 66 as US 60) that detailed some never-used plans, i.e. Route 13 along today's Route 17/I-880?

[agentsteel53]

I'd be more than happy to check out those PDFs! 

need an email address.  Send it via private message if you'd like.

Was there a "preliminary" map released in 1934 in the vein of the early US highway maps (the ones that showed US 66 as US 60) that detailed some never-used plans, i.e. Route 13 along today's Route 17/I-880?

I do not believe that the 1934 August I have is so preliminary - a lot of the routes check out as having been signed in their locations; in fact 28 is the only one about which I've heard that it may not have ever happened.  I do not know of any older maps that are more preliminary.  The August '34 is the only one I've ever seen.

[roadfro]

does this mean the oldest Nevada state route markers are 1933?

My previous post probably wasn't a clear as it could have been...

The road that is now SR 28 was shown on the 1932 map, but the SR 28 number itself wasn't put on the state map until 1933.  There are several other highway numbers shown on the 1932 map, including SR 27 (now SR 431) which ends at SR 28.

[TheStranger]

The road that is now SR 28 was shown on the 1932 map, but the SR 28 number itself wasn't put on the state map until 1933.  There are several other highway numbers shown on the 1932 map, including SR 27 (now SR 431) which ends at SR 28.

This would mean that...

1. SR 28 is the only vestige of the pre-1976 Nevada numbering system
2. It would also be the first time CalTrans created a route number (Route 28) as an intentional continuation of another state's #, which isn't particularly common even now.  (IIRC, California's Route 266 came before Nevada's, which somehow fits in with the Nevada numbering system as witnessed with the nearby NV 264)

[TheStranger]

Thanks for the PDFs, Jake!

It looks like several routes have existed almost unmodified (basically same corridor, with no extensions) from 1934 to now:

4, 23, 25, 27, 29, 32, 36, 45, 89, 94, 104, 120, 127, 132, 152, 166, 198

Also interesting to see unsigned/unbuilt extensions planned that early on:

Route 180 west of Route 33 to Route 25
Route 190 and 168 across the Sierras
Route 12 west to Route 1
The Route 39 "gap" between Fullerton and Azusa
Route 1 north of Leggett
Today's Route 128 (planned in 1934 as Route 28) east of I-505 to Davis

There's even a Route 180 extension planned in 1934 east through Kings Canyon! 

[roadfro]

The road that is now SR 28 was shown on the 1932 map, but the SR 28 number itself wasn't put on the state map until 1933.  There are several other highway numbers shown on the 1932 map, including SR 27 (now SR 431) which ends at SR 28.

This would mean that...

1. SR 28 is the only vestige of the pre-1976 Nevada numbering system
2. It would also be the first time CalTrans created a route number (Route 28) as an intentional continuation of another state's #, which isn't particularly common even now.  (IIRC, California's Route 266 came before Nevada's, which somehow fits in with the Nevada numbering system as witnessed with the nearby NV 264)

SR 88 is also a pre-1976 Nevada route number--the route was established as SR 37 in the mid 1930s, but changed to SR 88 in the mid 1950s for route number continuity with California.  SR 140 is also a pre-1976 Nevada number, which was almost changed to 291 in the renumbering.

I currently have no way of knowing when Nevada's SR 28 was first designated, other than the map evidence presented above. Given the sequential nature of the routes on the Nevada side, I would speculate that SR 27 and 28 were established as state highways around the same time.