California/2022 Highway Classification Guidelines

From OpenStreetMap Wiki
Jump to navigation Jump to search

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) was highway=primary, tagged August, 2022 as logical highway=trunk. These segments ARE tagged expressway=no to distinguish expressway=yes tags on trunk (Hwy 1 / Cabrillo Highway) connecting each end (W of Swift, N of Chestnut). Unknown is if alt_name=Cabrillo Highway is correct on Mission Street, though it IS Highway 1, but this 2.5 km non-expressway, retail- / professional- / commercial-zoned corridor with 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 I 15 intersection Yes Portions Other Principal Arterial No San Bernardino/Palm Springs ↔ 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 July 2022 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 CA 79 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 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 Co. 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 July 2022 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 Frankwood Rd. Yes Other Principal Arterial Primary + expressway=yes Primary + expressway=yes Does not connect population centers
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.