Explaining the California SH System

[agentsteel53]

for the benefit of everyone, I've uploaded the PDFs here:

www.aaroads.com/shields/misc/State_Route_Markers_Aug1934.pdf - 10MB
www.aaroads.com/shields/misc/State_Route_Markers_Oct1934.pdf - 5MB

[xonhulu]

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)

I know it's not exactly the same number, but who accommodated whom on the OR 39/CA 139 pair?

[national highway 1]

Well, I know that AZ 78 and AZ 264 continue into NM with the same number.

[TheStranger]

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)

I know it's not exactly the same number, but who accommodated whom on the OR 39/CA 139 pair?

Not sure how old Oregon Route 39 is, but Route 139 came around in 1946 according to Wikipedia (so pre-1964).

[KEK Inc.]

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)

The Klamath Falls-Malin highway should be upgraded to US-297.    

I know it's not exactly the same number, but who accommodated whom on the OR 39/CA 139 pair?

That whole route should be upgraded to US-297. 

[TheStranger]

While most post-1964 number assignments are on a (relatively) sequential basis, clustering still exists:

52, 54, 56 in metro San Diego
72 and 73 in Orange County
82, 84, 85, 87 in the Bay Area
92 and 93 (the existing segment of the latter not signed/maintained/built by CalTrans) in the Bay Area
102 and 104 (the former unbuilt) in metro Sacramento
unsigned 109, unsigned 114 (which was signed as 84 until the Bayfront Expressway/Marsh Road construction was completed about three years ago) and original 117 in the Bay Area (latter decommissioned in 1965)
129 and 130 in the South Bay
unbuilt 143 and 148 in metro Sacramento
original 163, unsigned 164 and original 165 in metro Los Angeles (163 and 165 decommissioned in 1965)
186 and 188 near the Mexican border (both commissioned in 1972)
212, 213, 214, and original 215 in metro Los Angeles (212, 214, and original 215 all decommissioned by the 1970s)
former 224 and current 225 in Santa Barbara
227 and 229 in San Luis Obispo County
former 231, current 241 and 261 in Orange County
unbuilt 234 and 235 in Stockton
236, 237, 238 along former Route 9 (mostly in the Bay Area) along with unbuilt 239 in the far Bay Area
former 240 and 243 (now I-605) in metro Los Angeles, along with former 245, former 248, unbuilt 249, former 250
254 and 255 in Humboldt County
unsigned 260 and 262 in Alameda County
263 and 265 in Siskiyou County
266 and 270 in Mono County
284 and unbuilt 285 in Plumas County

[xonhulu]

That whole route should be upgraded to US-297. 

Where would you take it on its southern end?  Routing it to Alturas would serve a little more traffic, but that wouldn't be a very long route.  Taking over 139 all the way to Susanville is longer, but that is a pretty empty stretch of country.

Not a very significant route as far as the cities it connects (K-Falls to either Alturas or Susanville, with stops in the metropolitises of Merrill, Doris and Tulelake), but I guess that's also true of US 197 up in Oregon/Washington, so that's not an insurmountable objection.  I wouldn't mind seeing US 297 here.