California/State Highway Relations

This page describes California state highway route and county highway route relations. Note that Interstate and US routes are distinctly omitted from this page. Interstate and US highways are included in California's statewide highway numbering protocol, as California state routes deliberately do not collide in their numbering with Interstate routes and US routes. See below about "logical extensions" at the boundary of an Interstate route and a California state route which share the same route number.

State Routes

Highways that are officially a State Highway Route with the green ("'49er miner's spade") California numbered highway sign. Use network=US:CA on the route=road relation, along with a ref=* tag with a value of the route number. These vary from one lane for traffic in both directions (e.g. segments of Highway 35 in the Santa Cruz Mountains) to freeway with as many as 12 total traffic lanes, including carpool lanes and parallel entrance/exit lanes (e.g. Highway 91 in Los Angeles, Riverside and San Bernardino Counties) — as well as most possibilities in between. All are fully paved. California state highway numbers do not duplicate Interstate or US highway numbers, unless the state highway is a physically-connected continuation of an Interstate as a "logical extension" (because it does not meet all of the physical standards for an Interstate). To be clear, a "logical extension" isn't actually an Interstate route, it is a state route that does not meet Interstate standards, while deliberately numbered the same as the Interstate, as it may be upgraded to Interstate in the future. For example, State Routes 15, 110 and 210 connect to Interstates respectively so numbered, exactly at the junction where the state route's physical standards fall below minimum Interstate requirements.

The California Department of Transportation (Caltrans) administers signed "Scenic Highways," legislatively defined as part of California's "State Scenic Highway System". Some highways are defined as being "eligible" for becoming a Scenic Highway, but have not (yet) been given this designation. For those highways which are so designated, especially when signed as such (a rectangular sign with an orange California poppy — the state flower — on a medium-blue background with snow-covered dark green mountains in the bottom-background), use network=US:CA:Scenic on a separate route=road relation to designate it as part of this statewide subnetwork. Exactly two California Historic Parkways are defined as a subset of the State Scenic Highway System (network=US:CA:Scenic) and should be additionally tagged with historic=yes.

Use unsigned_ref=* when a State Route exists but is unsigned, as well as to distinguish which State Scenic Highways are which (as some may be unsigned with the Scenic Highway shield). Do use unsigned_ref=* on a designated Scenic Highway route relation which is unsigned with the Scenic Highway shield, but do not use this tag on an "eligible" (but not officially designated by Caltrans) Scenic Highway.

There are also several County Routes — or segments of them — which have been designated "Scenic Highways," the only visible difference being the sign is the same except it is pentagonal instead of rectangular.

County Routes

California County Routes are designated by a letter followed by a number (e.g. "S2") on a distinct pentagonal blue shield. The letter indicates the zone the highway route is in (A, B, C, D, E, G, J, N, R, or S). A zone may cover multiple counties or split a county in two.^[1] The current county is clearly on the sign using this specific protocol. These "County Routes" are distinct from "State Routes" (numbered highways, above), and are in their own network in OSM. Use network=US:CA:CR.

County Routes — or segments of them — which have also been designated "Scenic Highways" on a separate route=road relation (the only visible difference being the sign is the same except it is pentagonal instead of rectangular) have this designation administered at the state-level by Caltrans along with the county, not solely at the county-level (all other administration / maintenance of County Scenic Routes is at the county-level). Use network=US:CA:CR:Scenic on the separate route=road relation.

Routes (roads) numbered at the individual county level into a single-county numbered network

This section is "early emerging." As more specific county data become available and better-known, please update relevant sub-sections. This includes creating a new sub-section for any county which has a numbered county road network.

These roads do not fit into the "alphanumeric" network (above, in the previous section), as there are no "zone letters" and these roads are geographically restricted to and are numbered and administered by a single county. They are in their own section in this wiki because they (mostly) diverge from the blue pentagonal signage of the alphanumeric network of County Routes. Exceptionally, the Lake County routes do use blue pentagonal signage, but are not state-coordinated (as is County Route 66 in San Bernardino County, above).

See Also

• Portal:California_roads
• County routes in California
• California/Freeway_ends

References