Highway Numbering in California

Numbering of California State Signed Routes

Before 1964, California routes had two distinct numbers: the number with which the route was signed, and the number with which the legislature identified the routes (LRN). A single LRN could be used over different sign routes, and vice-versa.

Routes were officially defined via legislative acts ("legislative routes"), and were initially established with legislation in 1909, when the first 25 routes were defined. At this time, the legislation only defined routes. Around 1916, numbers were assigned to the legislative routes; this list was maintained by the Division of Highways and was not part of the legislative code, except for occasional references. In 1935, the legislative route numbers became part of the State Highway Code through 1935 Chapter 29 Article 3. The legislative routes have been extended by legislative acts over the years. The original legislative numbers were never posted along highways, but were used on state highway maps and construction signage. While the state had one of the best highway marking programs in the country, originally the roads were marked primarily with the old trail signs – such as “Lincoln Highway”, “Old Spanish Trail" and “National Old Trails – rather than numbers.

Before 1934, the only routes that were signed in California were the US Highway routes (signage of these started in 1928). Once US Highways began to be signed, the state Division of Highways met with representatives of the auto clubs to adopt a route marker for state highways. There were a number of proposals (see figure below). In late 1934 the new program for signing state highways was announced. The group selected a "bear shield" design developed by the Division of Architecture, which resembled a miner's spade and displayed a grizzly bear taken from the California Bear Flag. They featured black figures on a white background, and were originally porcelain enamel on 18-gauge steel. The original intent was to have 3 signs per mile. After the state assigned sign route numbers to routes, they provided funds to the auto clubs to actually sign the routes.Auto Club signage of routes continued until 1956 in the southern portion of the state, and 1969 in the northern portion of the state, although the state had the primary responsibility of signing freeways.

The initial route numbering for state-signed routes was as follows:

• The odd/even to direction relationship is the same as for US Highways (i.e., odd is North/South, even is East/West).
• Route numbers are not duplicated with US Highway numbers signed in 1934.
• Smaller numbers are used primarily in major metropolitan areas.
• Route numbers are assigned in groups of two: two for Northern California, two for Southern California, two for Northern California, etc.
• Space has been left in the numbering plan for future routes.

There are some additional patterns that show up, but it is unclear if there were formal rules as no documentation has yet been found (again, note that these route numbers refer to the 1934 original route numbers, and skip the pre-1934 US routes):
(Source: Gribblenation Blog (Tom Fearer), “Patterns in the original 1934 California Sign State Route grid”, April 2022; as well as observations by this webmaster)

• Within the major cities, routes were generally ascending from W to E, and numbers would jump by 4 due to the northern/southern alternation. So in the San Francisco Bay Area, there would be Route 1, Route 5, Route 9, Route 13, Route 17; in Southern California there would be Route 3, Route 7, Route 11, Route 15, Route 19.
• For the laterals, there was one grouping that moved from N to S in Southern California (e.g., Route 2, Route 6, Route 10, Route 14, Route 18, Route 22) and another group in central and northern california that moved from S to N: Route 4, Route 8, Route 16, Route 20,Route 24, Route 28, Route 32, Route 36, Route 44. Again, jumps were by 4 due to the N/S split.
• There are other N/S patterns that can be seen: a grouping near Fillmore moving E (Route 23, Route 27, Route 35, Route 39), central valley route moving E (Route 33, Route 41, Route 45, Route 49), but the pattern isn't perfect.
• San Diego received a number of routes in the 70s, but there isn't a stronger descernable pattern. Both Route 74 and Route 78 were in the San Diego area, continuing to US 80. Route 70, Route 66, Route 62 were not defined in 1934. Route 58 takes us back to the central valley. Looking at the N/S routes, there was Route 71 and Route 79; Route 75 was defined in 1938 near Coronado.
• Route 94 and Route 98 were at the far Southern edge of the state (which supports the pattern of numbers increasing as one went S of Los Angeles); however, a number of earlier numbers were left open or reserved (Route 90, Route  86, Route 82 were not defined in the 1934 definitions)
• Route 96 was in the far northern part of the state. Route 92 wasn't assigned in the 1934 numbering; it could have been held in reserve for a route between Route 88 and Route 96 (it later went to the Bay Area).
• E/W routes in the Sierra were 3-digits, starting from Stockton at Route 104  ascending southward towards Visalia as Route 108, Route 120, Route 132, Route 140, Route 152, Route 168, Route 180 and Route 198.  From Visalia,  the State Routes descended southward to the Coast Range areas near Los Angeles as Route 190, Route 178, Route 166, Route 150, Route 138, Route 126 and Route 118. 

The image to the right shows some sign proposals from the Auto Club of Southern California.
(Image source: Yates Morgan, Archivist, Auto Club of Southern California)

It was noted on AARoads that many of the laterals in the central and southern part of the state were three-digit, ascending from L.A. northward until about Visalia, then descending again to about Stockton. Many of the routes had nearby routes with a difference of 12. So north of Route 126, you'll find Route 138, then Route 150 (today's Route 246/Route 154/Route 192). You'll see Route 166, Route 178, and Route 190; Route 152 and Route 140; Route 132, Route 120, and Route 108. But not everything fits this pattern, so this could just be the mind finding something.
(Source: AARoads Discussion - CA–118 and CA–126, April/May 2019)

As routes got added, an attempt was made to follow this, although it soon fell by the wayside, except for the even/odd usage.

As the state highway network grew, and existing roads became longer, each new segment was given its own number (but was an extension of the original signed route). This resulted in some state highways having up to 13 different legislative route numbers along their length. For example, Santa Monica Boulevard from the junction with US 101 was listed as Legislative Route Number 162 [LRN 162], State Signed Route 2 [Route 2], and US 66.

In 1959-60, all the old "miner's spade" "Grizzly Bear" highway markers were replaced by plain white "miner's spade" shields, without the Bear. This was the exact design of today's shields, except white in color instead of green. There are a few of these shields still around; in particular, around Route 126 in Ventura and the older portions of Route 134 in Glendale.

Tom Fearer has a detailed exploration of the change in signing standards in California in the blog "The last 1956-63 era California Sign State Route Spade?". This includes the original sign proposals from CSAA and ACSC, the evolution of the white shield, and the differing state signage standards.

In 1964, all state routes were renumbered to bring their legislative route number in sync with their signed route number (see the Mar/Apr 1964 issue of CHPW). There was also a renumbering to retire some US highway numbers, and to sign with Interstate route numbers [There is a good article on this renumbering at http://www.gbcnet.com/ushighways/history/1964_hwy_renumbering_contents.html].This removed any remaining semblance of order in the numbering of state highways. The routes were signed with a green shield, still in the shape of a miner's space, but lacking the grizzly bear. The new color was chosen for its visibility in hazy or foggy driving conditions, as well as the fact that new signage requirements required that shields on guide signs needed to match the shields on the road, and green shields allowed the use of outlines instead of actual shields (which were required with the white signage).

There were a number of reasons for the renumbering. First and foremost, the goal was to move to a "one route, one number" system. This meant getting rid of duplication and conflicting route numbers (such as having both US 40 and I-40), having routes signed with multiple numbers, having signed routes being legislatively multiple different numbers. The new system was intended to have a minimal concurrencies (although some US highways remained signed until their replacement Interstates were completed).

Numbering of Federal Highway System (US) Routes Exit Numbers

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Maintained by: Daniel P. Faigin <webmaster@cahighways.org>.