California/2022 Highway Classification Guidelines

This page documents the importance-based classification of trunk roads in California, following the principles of United States/2021 Highway Classification Guidance. Under this framework, roads classified as motorway and trunk together comprise a network of the best roads connecting all important population centers. As of May 2022, roads in California are sometimes tagged as trunk to indicate that they have some expressway characteristics, such as being divided, having relatively high speed limits, and/or limited access. Under an importance-based trunk system, these attributes can be expressed with other tags, such as maxspeed=* values and expressway=yes.

Below are four tables: a of list population centers in California and surrounding areas which should be linked to the statewide trunk network, a list of the roads which provide these inter-regional trunk connections (that is, connections between population centers in California and surrounding areas which are not already linked by motorways), a list of some notable roads not proposed for trunk classification, and a list of urban expressways with some tagging recommendations, attempting to follow consistent guidelines. This page builds on the work in User:Btwhite92/Draft:California Highways, which made classification suggestions for the Northern portion of the state. This proposal was initially drafted in December 2021 by User:willkmis, and has since been subject to discussion on OSMUS Slack and in other forums. As of July 2022, the trunk network has been implemented statewide on OpenStreetMap, with changesets related to this effort tagged with the hashtag #ca-highway-classification, as well as the national tag #us-highway-classification.

This page currently reflects an attempt to achieve consensus on differentiating only the trunk/motorway network from roads of lower classification. Future phases will aim to further delineate consensus on distinguishing between lower classification roads in California.

Determining roadway classification

Motorway

Freeways. This includes all interstate highways, as well as many portions of US, state, and occasionally local highways. Must adhere strictly to the following criteria:

• Divided carriageway
• Full access control
• Access by on/off ramp only (except for freeway beginning/endings, which are handled below)

California posts white regulatory "Begin Freeway" and "End Freeway" fairly rigorously at the beginning and ending of freeways. So long as the roadway meets the above criteria, highway=motorway tagging should begin and end at this signage where it is present, and the signs themselves tagged with traffic_sign=US:CA:R57 for "Begin Freeway" and traffic_sign=US:CA:R58 for "End Freeway". See California/Freeway ends for documentation of the location and existence of this signage on all California freeway beginning/endings, as well as how to handle cases where signage is not present or posted in an invalid location.

Trunk

Trunk roads carry principal "long-haul" connections between major population centers in the absence of a motorway. Typically, the majority of the length of a trunk road is built to a high standard, allowing high-speed travel and often carrying a noticeable amount of freight traffic. In mountainous areas, these roads typically have frequent passing lanes and smoother curve geometry than other highways. Short segments along the highway may not be built to the same standard, especially in downtown business districts, but nevertheless they are tagged consistently with connecting segments. Many of these roads carry current US highway alignments or formerly carried now-abandoned alignments. The latter are more common in California than elsewhere, as most of the state's former US highways were eliminated in a 1964 highway renumbering.

There is no single deterministic way to classify trunk roads, and there are many factors to consider. A roadway being part of the National Highway System, designated as an "Other Principal Arterial" or higher on state functional classification maps, or being part of a Strategic Interregional Corridor may be indicative of a trunk road, but not necessarily conclusive, as each of these metrics was designed for a slightly different purpose.

Ideally, there should be few enough community-approved trunk routes in CA that they can be enumerated in a table like below. Once this table is fairly settled, tagging guidance should encourage those that think a route should be/not be tagged as highway=trunk based on importance to consult with the local community first before making any changes.

To display all highways currently tagged as trunk in California, use this overpass query (below).

[out:json][timeout:50];
// fetch area “California” to search in
{{geocodeArea:California}}->.searchArea;
// gather results
(
  // query part for: “highway=trunk”
  way["highway"="trunk"](area.searchArea);
);
(._;>;);
out skel qt;

Proposed California population centers of inter-regional importance

These are the population centers in California and surrounding regions that are of sufficient inter-regional importance to merit connection to the state's highest-level road network. If not already connected via motorway, the fastest route between any two of these cities should be a trunk route. To define a "major" population center, a rough boundary of ~50,000 residents has been used. This roughly correlates to the prevailing benchmark used for place=city in California, though the exact centers chosen may depend on other measures of "inter-regional importance." Populations have been included alongside potential edge cases. Cities are (arbitrarily) grouped into three regions for ease of comprehension: "Northern", being roughly north of I 80, "Central", being between I 80 and Bakersfield, and "Southern", being south of Bakersfield. In dense urban regions, not every city that could qualify for trunk routing is listed here, as many urban links are already built to motorway standards. Instead, only urban/suburban cities which are important to potential trunk (i.e. non-motorway) routings are listed.

Northern	Central	Southern	Out of state	Not currently included, but potentially borderline
Eureka Redding Santa Rosa Napa Chico Yuba City Roseville Sacramento	San Francisco Bay Area San Rafael (pop 59k) Fairfield Vallejo Antioch Livermore Tracy Santa Cruz (pop 65k) Half Moon Bay/Pacifica (combined pop 50k) Monterey/Pacific Grove (combined pop 43k) Salinas Stockton Modesto Merced Fresno Hanford (pop 56k) Visalia Porterville (pop 60k) Bakersfield San Luis Obispo Santa Maria Lompoc (pop 42k) Santa Barbara	Oxnard Santa Clarita Lancaster Palmdale Victorville Santa Monica Los Angeles Long Beach Santa Ana Huntington Beach Newport Beach San Clemente (pop 65k) Ontario San Bernardino Riverside Hemet Temecula Indio Oceanside Escondido San Diego El Centro (pop 44k)	Coos Bay, OR Medford, OR Bend, OR Boise, ID Reno, NV Carson City, NV Las Vegas, NV Flagstaff, AZ Phoenix, AZ Yuma/Tucson, AZ Mexicali, BC Tijuana, BC	Clear Lake/Lakeport (combined pop 20-25k) Grass Valley (pop 13k) Oroville (pop 15k) Petaluma (pop 61k) Gilroy (pop 56k) An "edge to watch." Gilroy is the southern edge of Caltrain, San Joaquin and ACE/Valley Rail, part of Coast (Starlight, potentially Daylight) services via Amtrak™ and will be a station on future California High Speed Rail. Watsonville (pop 53k) Tulare (pop 59k) Cambria (pop 6k)/Morro Bay (pop 12k) Laguna Beach (pop 23k) Palm Springs (pop 49k) Twentynine Palms/Joshua Tree/Yucca Valley (combined pop 50k)

Proposed inter-regional California trunk routes

These routes serve as the "best" connections between major population centers/regions, which are not currently fully constructed to motorway standards. Together with motorways, they create California's main network of the "best" roads between regions. To define a "major" population center, see the table above. Trunk roads fully within urbanized areas may require different considerations, and are therefore cataloged in a separate table further below. The format of this table and classification suggestions for the northern region are mostly copied from User:Btwhite92/Draft:California Highways. Roads are (arbitrarily) divided into three regions for ease of comprehension: "Northern", being roughly north of I 80, "Central", being between I 80 and Bakersfield, and "Southern", being south of Bakersfield.

Region	Route	Start	End	NHS	FC	CA SIC	Regional Connection Served (Non-exhaustive)	Current tagging as of July 2022	Notes
Statewide	US 101	I 5	OR state line	Yes	Other Fwy or Expy, Other Principal Arterial	Yes	Coos Bay, OR ↔ Eureka ↔ Santa Rosa ↔ Bay Area ↔ Salinas ↔ SLO ↔ Santa Barbara ↔ Oxnard ↔ LA	Fully upgraded to trunk.	Matches proposed trunk tagging in Oregon Completed in changeset 115933261
Statewide	US 395	I 15	CA 299 intersection in Alturas	Yes	Other Principal Arterial	Portions between NV border and I 15 and CA 36 and NV border	San Bernardino ↔ Carson City/Reno, NV ↔ Bend, OR	Trunk
Northern	CA 139	CA 299 intersection in Canby	OR state line	Yes	Other Principal Arterial	No	Reno, NV ↔ Bend, OR	Trunk	Matches proposed trunk tagging in Oregon
Northern	CA 299	CA 139 intersection in Canby	US 395 intersection in Alturas	Yes	Other Principal Arterial	No	Reno, NV ↔ Bend, OR	Trunk
Northern	US 199	Crescent City	OR state line	Yes	Other Principal Arterial	No	Eureka ↔ Medford, OR	Trunk	Matches proposed trunk tagging in Oregon
Northern	US 50	Sacramento	NV state line	Yes	Other Fwy or Expy, Other Principal Arterial	Yes	Sacramento ↔ Carson City, NV	Trunk/motorway	Matches current trunk tagging in Nevada
Northern	US 97	Weed	OR state line	Yes	Other Fwy or Expy, Other Principal Arterial	No	Redding ↔ Bend, OR	Trunk	Matches proposed trunk tagging in Oregon Completed in changeset 115989234
Northern	CA 99	Sacramento	Red Bluff	Yes	Other Fwy or Expy, Other Principal Arterial	Portions between Red Bluff and CA 149 and between CA 70 and Sacramento	Redding ↔ Chico ↔ Sacramento	Trunk/motorway	Former US highway; many portions freeway/expressway, parallels CA 70/149
Northern	CA 70/149	CA 99 south interchange	CA 99 north interchange	Yes	Other Fwy or Expy, Other Principal Arterial	Yes	Chico ↔ Oroville (pop 15k) ↔ Yuba City ↔ Sacramento	Motorway/trunk	Parallels CA 99 on opposite side of Feather River
Northern	CA 299	Eureka/Arcata	CA 44 intersection in downtown Redding	Yes	Other Principal Arterial	Yes	Eureka ↔ Redding	Trunk, some motorway	Represents consensus after discussion in changeset 116088255 comments
Northern	CA 36/44	CA 299 intersection in downtown Redding	US 395 intersection	Yes	Other Principal Arterial	Yes	Redding ↔ Reno, NV	Trunk, some motorway	Represents consensus after discussion in changeset 116088255 comments
Northern	CA 89	CA 44 intersection	I 5 intersection	Yes	Other Principal Arterial	No	Medford, OR ↔ Reno, NV	Trunk
Northern	CA 20/53/29	US 101 intersection	I 80 intersection	Yes	Other Principal Arterial	Yes	Eureka ↔ Yuba City ↔ Reno, NV	Trunk	Trunk route follows south around Clear Lake - Caltrans documentation states CA 20 north of Clear Lake is geographically constrained and that highway development will be focused on the southern portion of the loop
Northern	CA 65	Roseville	Yuba City/Marysville	Yes	Other Fwy or Expy, Other Principal Arterial	No	Roseville ↔ Yuba City	Motorway/trunk	Mostly freeway or expressway; short two-lane highway segment
Northern	CA 29	CA 37 intersection	End of freeway in Napa	Yes	Other Fwy or Expy, Other Principal Arterial	No	Vallejo ↔ Napa	Trunk/motorway
Northern	CA 37	US 101 intersection	I 80 intersection	Yes	Other Fwy or Expy, Other Principal Arterial	No	San Rafael ↔ Fairfield/Sacramento	Trunk/motorway
Central	CA 12	Split with CA 121	I 5 intersection	Portion between Fairfield and CA 99	Other Principal Arterial between Fairfield and CA 99, Minor Arterial between CA 121 and I 80	No	Napa ↔ Fairfield ↔ Stockton	Trunk, some expressway
Central	CA 4	Antioch	CA 99 intersection	Only portion near Stockton	Other Principal Arterial	No	Antioch ↔ Stockton	Trunk
Central	CA 17	San Jose	Santa Cruz	Yes	Other Fwy or Expy	No	San Jose ↔ Santa Cruz	Motorway/trunk + expressway=yes
Central	CA 1	Santa Cruz' Mission at Chestnut	End of freeway in Carmel	Yes	Other Fwy or Expy, Other Principal Arterial	No	Santa Cruz ↔ Monterey	Motorway/trunk	See Notes in next row
Central	CA 1	Santa Cruz' Mission at Swift	Hwy 1 at Westport Drive, Pacifica (also serves Half Moon Bay; per Control City signage)	Portion north of Half Moon Bay	Other Principal Arterial north of HMB, Minor Arterial between HMB and SC	No	Santa Cruz ↔ San Francisco Bay Area	Trunk	Santa Cruz' Mission Street from Swift to Chestnut, ~2.5 km, (4-lane, 25 MPH speed limit heavily-signalized arterial) is tagged as logical highway=trunk. These segments ARE tagged expressway=no to distinguish expressway=yes tags on trunk (Hwy 1 / Cabrillo Highway) connecting East end of Mission (N of Chestnut, to Hwy 1 at River Street, known locally as "the Bypass"). Unknown is if alt_name=Cabrillo Highway is correct on Mission Street (believed so), while it IS Highway 1, this 2.5 km non-expressway, retail- / professional- / commercial-zoned corridor with (including elementary school-crossing) pedestrian traffic connects Cabrillo Highway (between Half Moon Bay / Pacifica and Monterey / Carmel) as "all trunk," much of it (from Santa Cruz to Carmel) as motorway.
Central	CA 68/ Blanco/ Sanborn	CA 1 intersection	US 101 intersection	Yes	Other Principal Arterial	No	Monterey ↔ Salinas/SLO	Motorway/trunk	Sanborn exit from US 101 signed as "Monterey Peninsula" in both directions, supporting trunk classification
Central	CA 183	CA 1 intersection	US 101 intersection	No	Minor Arterial	No	Santa Cruz ↔ Salinas	Primary
Central	CA 129	CA 1 intersection	US 101 intersection	No	Minor Arterial	No	Santa Cruz (County, the southernmost portion) ↔ Central Valley	Primary
Central	CA 156	CA 1 intersection	CA 152 intersection	Yes	Other Principal Arterial	Portion between US 101 and CA 152	Monterey/Salinas ↔ Central Valley	Trunk, some expressway=yes	WB signed from US 101 to "Monterey Peninsula", supporting trunk classification. EB signed from US 101 to Hollister.
Central	CA 152	US 101 intersection	CA 99 intersection	Yes	Other Principal Arterial	Portion between US 101 and I 5	San Jose ↔ Fresno	Trunk, some expressway=yes	Signed from US 101 to Pacheco Pass.
Central	CA 59	CA 152 intersection	CA 99 intersection	No	Minor Arterial	No	San Jose ↔ Merced	Trunk
Central	CA 198	I 5 intersection	CA 65 intersection	Yes	Other Principal Arterial	No	Bay Area ↔ Hanford ↔ Visalia ↔ Porterville	Trunk/motorway, some expressway
Central	CA 41	Fresno	CA 46 intersection	Yes	Other Principal Arterial	Yes	Fresno ↔ SLO	Trunk, some expressway
Central	CA 46	US 101 intersection	CA 99 intersection	Yes	Other Principal Arterial	Portion between US 101 and I 5	Salinas/SLO ↔ Bakersfield	Trunk, some expressway
Central	Betteravia/ CA 135/ CA 1	US 101 at Betteravia	US 101 at Las Cruces	Yes	Other Principal Arterial	No	Santa Maria ↔ Lompoc ↔ Santa Barbara	Trunk, expressway between CA 135 and Lompoc	Betteravia exit is signed on SB US 101 as connection to Lompoc
Central	CA 166	US 101 intersection	CA 99 intersection	No	Minor Arterial	No	Santa Maria ↔ Bakersfield	Trunk	Signed to Maricopa/Bakersfield from US 101
Central	CA 58	I 5 intersection	I 15 intersection	Yes, though along old route west of Bakersfield	Other Principal Arterial	Yes	Bay Area/Central Coast ↔ Bakersfield ↔ Lancaster ↔ Las Vegas, NV	Motorway with small trunk gaps east of Bakersfield, trunk/motorway through/west of Bakersfield (partly under construction)
Southern	CA 14	US 395 intersection	I 5 intersection	Yes	Other Fwy or Expy, Other Principal Arterial	Yes	Carson City/Reno, NV ↔ Lancaster ↔ Los Angeles	Motorway/trunk
Southern	CA 138	I 5 intersection	I 15 intersection	Portion from I 5 to CA 18	Other Principal Arterial, except Minor Arterial between CA 18 and I 15	No	Bay Area/Central Coast ↔ Lancaster ↔ Victorville/San Bernardino	Trunk
Southern	CA 18	CA 138 intersection	I 15 intersection	Yes	Other Principal Arterial	No	Lancaster ↔ Victorville	Trunk
Southern	CA 126	US 101 intersection	I 5 intersection	Yes	Other Fwy or Expy, Other Principal Arterial	No	Oxnard ↔ Santa Clarita/Central Valley	Trunk/motorway
Southern	CA 1	US 101 split	beginning of I 10	Most except between Pt Mugu and Trancas Beach	Other Fwy or Expy, Other Principal Arterial	No	Oxnard ↔ Malibu ↔ Santa Monica	Trunk/motorway
Southern	CA 79	I 10 intersection	CA 74 in Hemet	Yes	Other Principal Arterial/Minor Arterial	No	San Bernardino/Palm Springs ↔ Hemet	Trunk
Southern	CA 74	I 215 intersection	CA 79 in Hemet	Yes	Other Principal Arterial	No	Hemet ↔ Temecula	Trunk
Southern	CA 55	Costa Mesa	Intersection with Via Lido	Yes	Other Fwy or Expy	No	Los Angeles ↔ Newport Beach	Trunk, some expressway portions
Southern	CA 1	CA 22 intersection	CA 55 intersection	Yes	Other Principal Arterial	No	Long Beach ↔ Huntington Beach ↔ Newport Beach	Trunk
Southern	CA 76	I 5 intersection	I 15 intersection	Portion between I 5 and Bonsall	Other Fwy or Expy and Other Principal Arterial between I 5 and Bonsall, Minor Arterial beyond	No	Oceanside ↔ Temecula/Riverside	Trunk + expressway
Southern	CA 86	I 10 intersection	I 8 intersection	Yes	Other Principal Arterial	Portion north of Brawley	Indio ↔ El Centro/Mexicali, BC	Trunk, some expressway
Southern	CA 78	Split from CA 86	Split from CA 111	Yes	Other Principal Arterial	Yes	Indio ↔ Mexicali, BC	Trunk, some expressway
Southern	CA 78	Split from CA 111	I 10 intersection	No	Minor Arterial	No	Las Vegas, NV ↔ El Centro/Mexicali, BC	Trunk
Southern	CA 111	Split from CA 78	Mexican Border	Yes	Other Principal Arterial	Yes	Indio ↔ Mexicali, BC	Trunk, expressway north of Calexico	Matches current trunk tagging in Mexico
Southern	CA 7	I 8 intersection	Mexican Border	Yes	Other Principal Arterial	Yes	Yuma, AZ ↔ Mexicali, BC	Trunk + expressway	Matches current trunk tagging in Mexico
Southern	US 95	I 10 intersection	NV border	Portion north of I 40	Portion north of I 40 Other Principal Arterial, portion south Minor Arterial	No	Las Vegas, NV ↔ El Centro/Mexicali, BC	Trunk

Other notable inter-regional roads NOT currently proposed to be trunk

This table lists a selection of roads that are not included in the proposed trunk network. It includes inter-regional roads which were tagged as trunk as of Dec 2021 but were downgraded as part of the implementation, roads that meet some of the specific criteria laid out above but do not subjectively qualify, or other roads that have potential arguments for and against. If currently tagged as trunk, this proposal recommends downgrading the segments below to primary or lower, and potentially adding expressway=yes when merited. Roads currently tagged as trunk which lie in urbanized areas are cataloged in a separate table further below, as different considerations may apply.

Region	Route	Start	End	NHS	FC	CA SIC	Current tagging as of April 2023	Notes
Northern	US 395	CA 299 intersection in Alturas	OR state line	Yes	Other Principal Arterial	No	Primary	Discussed on the talk page. Reno-Bend trunk route follows CA 299 to CA 139 to OR 39. Potentially best route between Redding-Boise, but very desolate and low-traffic in Oregon, and still 9 hr (vs 10 hr via Bend or Reno). Primary classification matches proposed tagging in Oregon. May need further discussion.
Northern	CA 299	CA 139 intersection in Canby	Redding	No	Minor Arterial	No	Primary	Potentially best route between Redding-Boise, but see note for US 395 above.
Northern	CA 139	CA 299 intersection in Canby	CA 36 intersection in Susanville	No	Minor Arterial	No	Primary	Sometimes faster according to routing engines than parallel US 395, but US 395 offers the "best" route between Reno and Bend. CA 139 has steep grades and is avoided by freight. It also has lower traffic counts and a lower functional classification than parallel US 395. See discussion on the talk page.
Northern	Skyway Road	CA 99 intersection	Paradise	No	Minor Arterial	No	Secondary + expressway=yes	Not the "best" route between any two population centers: Paradise (pop. <30k) is not a major population center.
Northern	CA 49	Auburn	Grass Valley/Nevada City	Yes	Other Principal Arterial	Yes	Primary, short motorway segment near CA 20 intersection	Designated by Caltrans as a strategic inter-regional corridor between I 580 and CA 99, links Sacramento to Grass Valley. But, not the "best" route between any two population centers: Grass Valley (pop. 13k) is not a major population center. Possible candidate for expressway=yes
Northern	CA 20	CA 29 intersection	CA 53 intersection	No	Other Principal Arterial	No	Primary	Trunk route follows south around Clear Lake - Caltrans documentation states CA 20 north of Clear Lake is geographically constrained and that highway development will be focused on the southern CA 29/CA 53 corridor
Northern	CA 29	CA 53 intersection	End of freeway in Napa	Portion south of Yountville	Other Principal Arterial south of Yountville, minor arterial north of Yountville	No	Primary	Does not link major population centers, unless Clearlake/Lakeport (Lake County pop. 68k) qualifies. Then links Napa to Lake Co. Yountville (pop. 3k) is not a population center.
Northern	CA 116	US 101 intersection	CA 29 intersection	No	Minor Arterial	No	Primary	Despite appearing to link population centers, trunk network stub into Napa without clear connection to north and west matches local perception of road hierarchy
Northern	CA 1	US 101 intersection in Leggett	US 101 intersection in Mill Valley	No	Minor Arterial	No	Primary	Not the "best" route between any two population centers: through traffic between Eureka and Bay Area uses US 101
Central	CA 132	I 5 intersection	CA 99 intersection	Yes	Other Principal Arterial	Yes	Primary	Designated by Caltrans as a strategic inter-regional corridor between I 580 and CA 99. But, not the "best" route between any two population centers: fastest way between Bay Area and Modesto is via I 205/CA 120 freeways
Central	CA 88	CA 99 intersection	NV State Line	Yes	Other Principal Arterial	No	Primary	Open in winter, but the best way between Stockton and Carson City is via US 50
Central	CA 219	CA 99 intersection	CA 108 intersection	No	Other Principal Arterial	No	Primary	Potentially expressway=yes, but does not link population centers
Central	CA 108	Tuolomne-Stanislaus county line	Stanislaus Nat'l Forest	Up to Standard Rd.	Other Principal Arterial up to Standard Rd.	No	Primary and secondary, some expressway=yes	Does not link population centers. Not sure if it should even be primary east of Sonora
Central	CA 1	End of freeway in Carmel	US 101 intersection in SLO	Only first few miles out of SLO	Mostly Minor Arterial, but Other Principal Arterial between Atascadero Rd. and SLO	No	Primary north of Cayucos, trunk/motorway south	Not the "best" route between any two population centers: through traffic between Monterey and SLO uses US 101. Important tourist route/scenic byway, but windy, steep two-lane road through rough terrain. Portions between Cayucos/Morro Bay (pop. 12k) and SLO built to expressway/freeway standards, so left tagged as trunk in this portion pending further discussion.
Central	CA 46	CA 1 intersection	US 101 intersection	No	Minor Arterial	No	Primary	If CA 1 is classified trunk to Cambria, making CA 46 trunk would improve network connectivity
Central	Manning Ave.	CA 99 intersection	Reedley	No	Major Collector, except portion Other Principal Arterial in Parlier	No	Primary	Reedley (pop 25k) is not a population center.
Central	J40 (Mountain View, Ave. 416, El Monte)	CA 99 intersection	Orosi	No	Minor Arterial between CA 99 and Dinuba, Other Principal Arterial between Dinuba and Orosi	No	Primary	Dinuba (pop 25k) and Orosi (pop 9k) are not population centers.
Central	J19 (Road 80)	CA 99 intersection	Dinuba	No	Other Principal Arterial	No	Primary	Dinuba (pop 25k) is not a population center.
Central	CA 63	CA 137 intersection	CA 198 intersection	Portions within Visalia and Tulare	Other Principal Arterial	No	Primary	"Best" route between Bakersfield and Visalia is via CA 99/CA 198 freeways
Central	CA 190	CA 65 intersection	Blue Heron	Yes	Other Principal Arterial	No	Primary	Does not link population centers. Possible expressway=yes candidate. Maybe Porterville to I 5/points north?
Central	Lerdo Hwy.	CA 99 intersection	CA 46 intersection	Yes	Other Principal Arterial	No	Primary	Shafter (pop 16k) is not a population center.
Central	CA 43	Lerdo Hwy. in Shafter	CA 46 in Wasco	No	Minor Arterial	No	Primary	Wasco (pop 25k) and Shafter (pop 16k) are not population centers.
Central	7th Standard Rd.	CA 99 intersection	Santa Fe Way	Portion to Zenker Rd.	Portion to Zenker Rd.	No	Primary	Does not link population centers, through traffic uses parallel CA 58
Central	US 6	US 395 intersection	NV state line	Yes	Other Principal Arterial	No	Primary	Despite US highway designation, not the "best" route between population centers.
Central	CA 198	US 101 intersection	I 5 intersection	No	Minor Arterial	No	Primary	Based on feedback from user who has traveled this road over Coast Range, this is not a trunk connection: main route from US 101 to Central Valley is via CA 152 or CA 46. Those roads are built to higher standards, with fewer sharp curves and more freight traffic. Signed from US 101 with destination Coalinga
Central	CA 178	End of freeway at Canteria	US 395 intersection	No	Minor Arterial	No	Primary with brief motorway segment in Lake Isabella	Does not connect population centers: "best" route between Bakersfield and Inyokern/Carson City is via CA 58/US 395. Lake Isabella (pop 4k) is not a population center.
Central	CA 135	US 101 in Santa Maria	Betteravia Rd	Yes	Other Principal Arterial	No	Primary	Does not connect population centers, through traffic uses closely parallel US 101
Central	CA 154	Southern US 101 intersection in Santa Barbara	Northern US 101 intersection in Los Olivos	Only first couple miles in Santa Barbara	Minor Arterial except first couple miles in Santa Barbara	No	Primary	Sometimes faster by a few minutes than parallel US 101, but US 101 is "best" route between Santa Barbara and Santa Maria. CA 154 is narrow, windy, two lane road that does not connect to any major population centers on its own
Southern	CA 1	CA 55 intersection	I 5 intersection	Yes	Other Principal Arterial	No	Primary	From Newport Beach, "best" route to San Clemente and south uses freeway routes such as CA 55/I 405/I 5 or CA 73 rather than PCH
Southern	CA 133	I 405 intersection	CA 1 intersection	Yes	Other Principal Arterial	No	Primary, expressway=yes north of CA 73	Does not connect population centers: Laguna Beach (pop 23k) is not a population center.
Southern	CA 74	I 5 intersection	I 215 intersection	No	Minor Arterial	Yes	Primary	Designated by Caltrans as a strategic inter-regional corridor between I 5 and I 15. But, not the "best" route between any two population centers: fastest way between San Clemente and Temecula is via CA 76 freeway, and fastest way to Riverside is via CA 91 freeway
Southern	CA 79	I 15 intersection	CA 74 intersection	Yes	Other Principal Arterial	No	Primary	"Best" route between Temecula and Hemet is via I 215/CA 74, despite CA 79 being slightly more direct. Changed guidance in Apr. 2023 based on a local user's downgrade, see talk page.
Southern	Domenigoni Pkwy.	I 215 intersection	State St.	No	Minor Arterial	No	Primary + expressway=yes	Sees some through traffic to Hemet, but closely parallel to CA 74, so state route gets trunk tagging. Expressway tagging added in Apr. 2023.
Southern	CA 111	I 10 intersection	San Rafael Ave.	Yes	Other Principal Arterial	No	Primary + expressway=yes	Through traffic uses parallel I 10
Southern	CA 62	I 10 intersection	Twentynine Palms	Yes	Other Principal Arterial	No	Primary	Highway links no major population centers, despite being main route to Marine base and Joshua Tree NP

Urban expressways

In more built-up areas, different considerations may apply to determining whether a road should be classified as trunk. This table compiles some notable urban/suburban roads that could debatably be classified as trunk or a lower class. The table below includes all roads tagged as trunk as of Dec 2021 which are wholly within California's urbanized areas, though the cutoff between an urban and an inter-regional route is somewhat arbitrary. This includes urban expressways of varying levels of construction (e.g. Santa_Clara_County,_California#Expressways, San Diego Co. Parkways), continuations of inter-regional trunk routes through urbanized areas which are not built as motorways (e.g. US 101 in San Francisco, CA 178 in Bakersfield), and all other urban roads classified as trunk.

The recommendations below attempt to follow these guidelines:

(a) if a road closely parallels a motorway that connects to the same general area, then the motorway acts as the "best" route through the area, and the parallel road is only for local access and thus should not be tagged as trunk. Conversely, if a road is not closely parallel to a freeway, it may merit trunk tagging even if not constructed to expressway standards.

(b) If a road continues as a lower class road on either/both ends, this may be an indication that the road may not be a true trunk connection, but is tagged as trunk solely to indicate construction, which may be better conveyed using other tags such as speed limits or expressway=yes rather than road classification. Conversely, roads that continue on from the end of a motorway could merit trunk tagging if the destination served by the motorway (e.g. a population center, or a link to another motorway) lies beyond the end of the motorway.

(c) Connecting to the overall state motorway/trunk network is important, and classification should attempt to reflect the network. Spurs/dead-ends in the network are possible in certain cases (e.g. terminal geography, distribution to a network of lower class roads), but should be carefully scrutinized. Islands in the trunk network are highly unlikely, and probably merit re-classification.

Region	Route	NHS	FC	Current tagging as of Nov 2023	Recommendation	Notes
Northern: Redding	CA 273	Yes	Other Principal Arterial	Primary	Primary	Redding already linked to road network. Possible candidate for expressway=yes. Portions upgraded to trunk then reverted after discussion in changeset 116088255 comments. Primary classification except for brief concurrency with CA 44 represents current consensus.
Northern: Sacramento	Tower Bridge Gateway	No	Local	Secondary	Secondary	Very short segment coming off freeway, continues as a secondary
Northern: Sacramento	Watt Avenue	Yes	Other Principal Arterial	Primary + expressway=yes	Primary + expressway=yes	A few interchanges. Primary matches continuing road in both directions.
Central: Bay Area	Airbase Pkwy.	Yes	Other Principal Arterial	Primary + expressway=yes	Primary + expressway=yes
Central: Bay Area	CA 221: Napa-Vallejo Highway	Yes	Other Principal Arterial	Primary + expressway=yes	Primary + expressway=yes	Napa already connected to trunk network.
Central: Bay Area	Richmond Parkway	Yes	Other Principal Arterial	Trunk + expressway=yes	Trunk + expressway=yes	Long road, mostly at-grade intersections with a few separations. Might be OK as trunk, connects San Rafael to I 80/Sacramento
Central: Bay Area	CA 4: John Muir Skyway	Yes	Other Principal Arterial	Trunk + expressway=yes	Trunk + expressway=yes	Almost all motorway except for two-mile segment with at grade intersections in EB direction only
Central: Bay Area	Ygnacio Valley/Kirker Pass Rds.	Yes	Other Principal Arterial	Trunk	Downgrade to primary	Not sure this qualifies as trunk: may simply be a primary with some expressway segments. Walnut Creek and Pittsburg are already connected via freeway, and road is not all that different in apparent importance from intersecting primary roads.
Central: Bay Area	CA 160: Antioch Bridge	Yes	Other Principal Arterial	Trunk	Keep as trunk, add expressway?	Kind of a weird one: 2 lane, divided by concrete barrier. So maybe not quite a motorway, trunk suitable.
Central: Bay Area	Vasco Rd.	Only Alameda Co. portion	Other Principal Arterial	Trunk	Trunk	Connects Antioch and Livermore
Central: Bay Area	CA 84: I 580 to I 680	Only Isabel Rd. portion	Isabel Rd. is Other Principal Arterial, Vallecitos Rd. is Major Collector	Trunk	Trunk	Connects Livermore and South Bay
Central: Bay Area	CA 84: I 680 to I 880	Only west of Palomares	Other Principal Arterial west of Palomares, Major Collector east	Primary (brief trunk segment on Decoto)	Primary (brief trunk segment on Decoto)	Not a key route between centers. Left trunk on Decoto only to fully connect Dumbarton Bridge to I 880
Central: Bay Area	Hegenberger Rd.	Yes	Other Principal Arterial	Trunk, some expressway	Downgrade to primary	Equivalent in importance to other Oakland primaries. Only added expressway=yes between International and just west of San Leandro. Don't think rest of road qualifies as expressway, as there's direct access to driveways.
Central: Bay Area	Oakland Airport access roads	Yes	Other Principal Arterial	Trunk	Downgrade	No clear consensus as to how to tag airport access roads, examples within CA of primary (LAX), secondary (SAN), unclassified (SFO), and service (ONT, FAT). But does not merit trunk tagging
Central: Bay Area	CA 84: US 101 to Dumbarton Br.	Yes	Other Fwy or Expy	Trunk, expressway=yes	Trunk	Connects Peninsula and Hayward
Central: Bay Area	CA 262	Yes	Other Principal Arterial	Trunk	Trunk	Links Silicon Valley and Dublin/Livermore
Central: Bay Area	CA 237	Yes	Other Principal Arterial	Trunk	Trunk	Links Mountain View/CA 237 freeway to I 680
Central: Bay Area	Santa Clara Co. Expressways	All but Foothill Expy.	Other Principal Arterial	Trunk	Keep as trunk	A bit of a special case, should be tagged comparably to e.g. New York's parkways, which are trunk. Care should be taken to ensure connectivity. A few potential upgrades to enhance trunk connectivity: Page Mill Rd. between Foothill and El Camino, Alma between San Antonio and Oregon, Saratoga between Lawrence Expy. and CA 85
Central: Bay Area	Santa Teresa Blvd.	No	Minor Arterial	Primary	Primary
Central: Bay Area	Monterey Rd.	Yes	Mostly Other Principal Arterial	Trunk	Downgrade to primary	"Best" route is provided to all destinations by closely parallel US 101
Central: Bay Area	CA 35 north of 280	Yes	Other Principal Arterial	Primary + expressway=yes	Primary + expressway=yes	"Best" route is provided by closely parallel I 280. If kept as trunk, should be trunk on Sloat to 19th Ave to provide connectivity to CA 1
Central: Bay Area	CA 1 between US 101 and I 280	Yes	Other Principal Arterial	Trunk	Trunk	Provides regional connectivity as best route between Peninsula/South Bay (e.g. Daly City, Sunnyvale) and Marin
Central: Bay Area	US 101 in San Francisco	Yes	Other Principal Arterial	Trunk	Trunk	Provides regional connectivity as best route between portions of Peninsula (e.g. San Mateo) and Marin, and enhances trunk/motorway connectivity. However, Van Ness Ave. may not be "best" N-S route across San Francisco, compared to, e.g., parallel one-way couplet Gough/Franklin, despite carrying US 101 designation
Central: Bay Area	CA 1 south of I 280	North of Half Moon Bay	Other Principal Arterial north of Half Moon Bay, Minor Arterial south	Trunk between Pacifica (Westport Drive) and Santa Cruz (Swift Street)	Trunk	Provides network connectivity as only major road out of Pacifica. Population density dramatically declines south of Linda Mar.
Central: Bay Area	CA 92 west of I 280	No	Minor Arterial	Primary	Primary	Half Moon Bay is not a major population center, HMB and Pacifica together marginally might be
Central: Salinas	West Blanco Rd./Davis Rd.	Yes	Other Principal Arterial	Primary, some expressway	Primary, some expressway	Maybe expressway=yes, but only one interchange. Monterey-US 101/Salinas link served by Sanborn
Central: Salinas	East Blanco Rd./Sanborn Rd.	Yes	Other Principal Arterial	Trunk, some expressway	Trunk, some expressway	Serves Monterey-Salinas link
Central: Stockton	Arch Airport Rd.	East of McKinney	Other Principal Arterial east of McKinney	Primary	Primary	Some overpasses, but not long enough to qualify as expressway
Central: Tracy	West 11th St.	Yes	Other Principal Arterial	Primary	Primary	Through traffic uses closely parallel I 205
Central: Fresno	CA 180 to Reed Ave.	Yes	Other Principal Arterial	Trunk + expressway=yes	Trunk + expressway=yes	After discussion in https://www.openstreetmap.org/changeset/140555362, local consensus was to extend freeway stub as trunk stub to Reed Ave. as collector of suburban traffic into Fresno.
Central: Fresno	Golden State Blvd. to Kingsburg	No	Occasional Other Principal Arterial stretches through towns, otherwise Major Collector	Primary	Primary	Through traffic is carried by parallel CA 99 freeway.
Central: Bakersfield	Alfred Harrell Hwy.	Yes	Other Principal Arterial	Motorway	Potentially downgrade to secondary	Not sure this is a real motorway, but leaving for now. At minimum expressway=yes. Secondary matches endpoint classification.
Central: Bakersfield	Golden State Ave. between CA 99 and CA 178	Yes	Other Fwy or Expwy	Trunk	Trunk	Enhances network connectivity by connecting CA 178 freeway to rest of network.
Central: Bakersfield	CA 178: 23rd St/24th St	No	Other Principal Arterial	Trunk	Trunk	Enhances network connectivity by connecting CA 178 freeway to rest of network.
Central: Bakersfield	South Union Ave.	Yes	Other Principal Arterial	Primary	Primary	"Best" route for through traffic follows closely parallel CA 99
Southern: Los Angeles	CA 1: Oxnard to Santa Monica	Most except between Pt Mugu and Trancas Beach	Other Fwy or Expwy, Other Principal Arterial	Trunk/motorway	Trunk	Serves Oxnard to Santa Monica network link
Southern: Los Angeles	CA 90 west end, Marina Expressway	Yes	Other Fwy or Expwy	Trunk + expressway=yes	Trunk + expressway=yes	Connects Marina del Rey to freeway network
Southern: Los Angeles	CA 1 north of I 105	Yes	Other Principal Arterial	Primary + expressway=yes	Primary + expressway=yes	Road does not significantly change in importance from primary road it continues as on either end, just in construction. Does connect to LAX.
Southern: Los Angeles	La Cienega Blvd. between I 10 and I 405	Yes	Other Principal Arterial	Primary, with expressway=yes between Obama and La Tijera	Primary, with expressway=yes between Obama and La Tijera	"Best" route between Inglewood/South Bay and downtown Los Angeles is via I 405/I 10 or I 105/I 110 freeways, despite similar travel times. Either way, best to keep whole route same classification.
Southern: Los Angeles	CA 47: Alameda St.	Yes	Other Principal Arterial	Primary	Primary	Through traffic would take closely parallel I 710 freeway. Despite some grade separated intersections, don't think this qualifies as an expressway: too many cross streets, and grade separation is mostly quirk of being parallel to freight tracks.
Southern: Los Angeles	Ocean/Shoreline/Queens	Yes	Other Principal Arterial	Trunk + expressway=yes	Trunk + expressway=yes	Connects downtown Long Beach to freeway network, probably ok as trunk
Southern: Los Angeles	CA 22: 7th St	Yes	Other Principal Arterial	Trunk to CA 1	Trunk	Note: this has gone back and forth over the years, most recently switched from trunk in Mar 2021. Enhances connectivity with concurrent CA 1 classification upgrade
Southern: Los Angeles	CA 1: Los Alamitos Circle to CA 22	Yes	Other Principal Arterial	Primary	Primary	Note: this has gone back and forth over the years, most recently switched from trunk in Mar 2021
Southern: Orange County	CA 1: CA 22 to Newport Beach	Yes	Other Principal Arterial	Trunk	Trunk	Connects Huntington Beach to Long Beach and Newport Beach, far enough from parallel I 405 to serve as "best" route between coastal beach cities.
Southern: Orange County	CA 1: Newport Beach to I 5	Yes	Other Principal Arterial	Primary	Primary	From Newport Beach, "best" route to San Clemente and south uses freeway routes such as CA 55/I 405/I 5 or CA 73 rather than PCH
Southern: Orange County	CA 55: Newport Blvd.	Yes	Other Fwy or Expwy	Trunk	Trunk	Connects Newport Beach to motorway/trunk network
Southern: Orange County	CA 90: Nixon Parkway	No	Other Principal Arterial	Trunk + expressway=yes	Trunk + expressway=yes	Similar to San Jose expressways. Potentially optimal to extend trunk designation to I 605(or even to I 105 in Norwalk?) to enhance network connectivity.
Southern: Inland Empire	CA 18	No	Minor Arterial	Primary + expressway=yes	Primary + expressway=yes	Does not connect population centers, primary on either end.
Southern: Inland Empire	CA 71: Corona Freeway	Yes	Other Fwy or Expwy	Small stretch of trunk + expressway=yes near CA 55 junction	Trunk + expressway=yes	Kind of a weird case where motorway has one cross road (maybe private?)
Southern: Inland Empire	CA 60: Moreno Valley Fwy.	Yes	Other Principal Arterial	Small stretch of trunk + expressway=yes near I 10 intersection	Trunk + expressway=yes	Similar to CA 71 above. Are these small rural road intersections sufficient to downgrade a motorway?
Southern: Inland Empire	Ramona Expressway	No	Minor Arterial	Primary	Primary
Southern: San Diego	CA 76	Portion between I 5 and Bonsall	Other Fwy or Expy and Other Principal Arterial between I 5 and Bonsall, Minor Arterial beyond	Trunk + expressway=yes	Trunk + expressway=yes	Carries Oceanside-Inland Empire route
Southern: San Diego	CA 78 between I 5 and South Coast Hwy.	No	Minor Arterial	Secondary	Secondary
Southern: San Diego	South Coast Hwy.	No	Minor Arterial	Primary	Primary	Former US 101, superseded by nearby parallel I 5, which is the "best" route between the beachfront cities of North County.
Southern: San Diego	Centre City Pkwy.	Yes	Other Principal Arterial	Primary + expressway=yes	Primary + expressway=yes	Former US 395, superseded by nearby parallel I 15, which is the "best" route between Escondido and points north and south. Was primary until 2019, when it was upgraded to trunk.
Southern: San Diego	CA 56: Ted Williams Pkwy.	Yes	Other Principal Arterial	Trunk + expressway=yes	Trunk + expressway=yes	Urban expressway, logical continuation of CA 56 freeway, but dead ends in Poway with no connection to rest of network, so some case for primary
Southern: San Diego	Scripps-Poway Pkwy.	West of Sycamore Canyon	Other Principal Arterial	Primary + expressway=yes	Primary + expressway=yes	Does not connect population centers, was primary until upgraded in 2019 due to construction characteristics.
Southern: San Diego	CA 67 north of Lakeside	South of Vigilante	Other Principal Arterial south of Vigilante, Minor Arterial north	Primary, some expressway	Primary, some expressway	Does not connect population centers. Primary until upgraded to trunk in 2018.
Southern: San Diego	CA 94	Yes	Other Fwy or Expwy	Trunk + expressway=yes	Trunk + expressway=yes	Trunk stub at end of freeway until splits into two primaries, probably OK.
Southern: San Diego	CA 905	Yes	Other Fwy or Expwy	Trunk	Trunk	Stub at Otay Mesa border crossing, leave to maintain continuity with trunk on Tijuana side.
Southern: San Diego	Kearny Villa Rd.	Yes	Other Principal Arterial	Primary + expressway=yes	Primary + expressway=yes	Does not connect population centers. Has toggled between motorway and trunk in past. Former US 395.
Southern: San Diego	Fairmount Ave.	Yes	Other Principal Arterial	Trunk + expressway=yes	Downgrade to primary	Through traffic uses closely parallel CA 15, continues as primary and secondary on either end.
Southern: San Diego	Pacific Highway	Yes	Other Principal Arterial	Primary + expressway=yes	Primary + expressway=yes	Through traffic uses closely parallel I 5, continues as primary on either end.
Southern: San Diego	Friars Rd.	Yes	Other Principal Arterial	Trunk	Downgrade to primary, potentially add expressway=yes	Through traffic uses closely parallel I 8, continues as primary on either end. Kind of an in between one for expressway, access control ramps interspersed with stoplights, and not fully dual carriageway
Southern: San Diego	Sea World/Sunset Cliffs/Mission Bay	Yes	Other Principal Arterial	Primary, some expressway	Primary, some expressway
Southern: San Diego	Mission Bay/Ingraham	No	Other Principal Arterial	Secondary, some expressway	Secondary, some expressway	Secondary matches endpoints to north and west
Southern: San Diego	Nimitz Blvd.	Yes	Other Principal Arterial	Trunk + expressway=yes	Trunk + expressway=yes	Continuation of I 8 freeway
Southern: San Diego	CA 75	Yes	Other Principal Arterial	Primary, some expressway	Primary, some expressway	Coronado (pop 20k) is not an important population center, though an important military center.

Classifications below trunk

As of August 2022, this classification effort has focused on differentiating between the trunk/motorway networks and lower classifications. Less attention has been focused on differentiating between lower classes (primary/secondary/tertiary/etc.), though these also play an important role in the road network. Future phases of this work will attempt to gain consensus on tagging these highway values in California. Some guidelines have been provided in the United States/2021 Highway Classification Guidance, mostly emphasizing that network connectivity should be preserved at all levels. There is also long-standing guidance, which predates the guidelines on this page, on the California/Map features state guidelines. For one Californian mapper's perspective, see also this diary entry by User:willkmis.