California/Map features
This page is a supplement to Map features that describes how to map in California. Whereas Map features and other pages in the Key: and Tag: namespaces of this wiki offer general advice that applies globally, this page describes tagging conventions that are peculiar to California in OpenStreetMap and offers examples that are familiar to California residents.
Streets and highways
Highway classifications
- Main article: California/2022 Highway Classification Guidelines
Since there are multiple governments involved in building/maintaining roads, and there doesn't seem to be usable correlation of what they call a road to the values for highway=* used in OpenStreetMap, road types are assigned values by judgment. The following guidelines are for urban areas, and are loosened for rural and tightened in dense urban to avoid making everything secondary or larger in an area.
- highway=motorway – Freeways
- Access via on/off ramps with merge lanes, divided road of at least 2 lanes each direction.
- Speed limits generally 55 mph or higher.
- Look for
near the end of the freeway. - Look for
at the foot of each on-ramp. - If the highway is connected to surface streets, look for
at the intersection where the freeway begins and 
at the intersection where it ends.
- highway=trunk – Long-distance road that connects regional population centers, coordinated in this worklist. An expressway is no longer necessarily a trunk road; it may be classified lower if it serves more local traffic.
- highway=primary – Three lanes or more each traffic direction. 35 mph or faster. Handles large volumes of traffic. (Any or all of these).
- highway=secondary – Two lanes of traffic each direction. 35 mph or faster. Medium-high traffic volumes.
- highway=tertiary – Lower traffic volumes on wide streets, or higher traffic volumes on narrow ones. Sometimes called a "collector" (or "feeder") as it feeds traffic from residential and lower-classification highways to higher ones.
- An intersection with traffic lights connects at least one tertiary or higher street.
- An intersection with a one-way slip lane connects at least one tertiary or higher street.
- At any two-way stop intersection with an unclassified or residential road, the tertiary road has the right of way (highway=priority) while the unclassified or residential road must stop or yield (e.g.,
). - In urban areas, look for a painted stripe or median running down the centerline.
- In some cities, look for a bike lane or bus stops.
- highway=unclassified – Single traffic lane each direction. 35 mph or slower.
- highway=residential – Single traffic lane each direction, abutters residential, may also be oneway=yes. Usually 25 mph or slower. May have traffic bumps and other "traffic calming" measures.
If something has a county, state or federal highway route number, it can and often does get classified higher if there is a question.
In addition, use expressway=yes on expressways:
- May have cross traffic, but traffic flow on the trunk always has the right of way (except at red traffic lights).
- Speed limits usually 45 mph or higher.
- Look for
or Cross Traffic Ahead near the end of the expressway. - Look for
on turn lanes at intersections. - Look for on-ramps without (with some exceptions).
Caltrans designates multiple kinds of truck routes with distinct signs:
- National Network (for interstate "STAA" trucks): hgv=designated hgv:national_network=yes
National Network Terminal Access: hgv=destination hgv:national_network=terminal_access
National Network Service Access: hgv=destination hgv:national_network=service_access- Other truck routes (for "California Legal" trucks): hgv=designated hgv:national_network=no
Speed limits
- 65 MPH is the maximum speed limit on multi-lane divided highways unless otherwise posted (though the limit on such roads is generally well-signed) CVC 22349. There are some segments of rural highway (e.g. 101 in parts of the Salinas Valley) which are signed 70 MPH.
- Business areas/residential areas: 25 MPH unless otherwise posted CVC 22352(b)(1)
- Otherwise, the maximum speed limit is 55 MPH unless otherwise posted CVC 22349(b)
Bridges
Bridge overcrossings and undercrossings are systematically named and numbered throughout the state highway system. When mapping a man_made=bridge area, use the state highway bridges and local bridges datasets from Caltrans to easily determine the name and number that are stamped on the bridge, as well as the height restriction on any roadway below. (Consult the standard Caltrans abbreviations for the full expanded words to use in name=*.) This Caltrans document lists the official names of bridges and tunnels. There is no established tag for naming an underpass (undercrossing in Caltrans jargon), but underpass=yes underpass:name=* has been tagged on some short roadway segments.
Road signs
Road signs are tagged with traffic_sign=*; most values start with US:, followed by standard sign code, but California-specific signs start with US:CA:. MUTCD/California lists each sign code in the California MUTCD and its equivalent tags.
Points of interest
Car repair
Test-only smog check stations are tagged amenity=vehicle_inspection. Car repair shops that also offer smog checks are tagged shop=car_repair service:vehicle:smog_check=yes. If the smog check station is part of the STAR program, add network=STAR network:wikidata=Q85269938.
Energy distribution
EV charging
There are many electric-vehicle charging stations in the state. The accepted way to tag these is with the combination of amenity=fuel and fuel=electricity, even where there is no real (liquid) fuel available at a station.
A new tag amenity=charging_station has been proposed and is actively being developed. It is intended to cover details unique to EV charging stations, but not all of its details have been worked out yet. If you wish to have input on how it develops, see Proposed features/Charging station. It is intended to replace the two-tag combination above (though of course amenity=fuel would still be used at locations that have both fuel and chargers).
Utility markers
Many natural gas pipelines owned by the Pacific Gas and Electric Company and the Sacramento Municipal Utility District are marked by rhombus-shaped signs on posts, which are tagged marker=paddle.
Protected areas
Protected areas include state parks, wildernesses, natural reserves, protected marine areas, etc. There is an OSM trend towards states and the USA using "protected area databases" to curate / include data, especially where they would otherwise remain unknown (or there is some dispute over, say, an exact boundary). In California, this is the California Protected Area Database (CPAD). California/Using_CPAD_data is a wiki explaining the data format and suggests sensible logical mappings from CPAD tags to OSM tags using a simple, table-driven scheme. For a more national scope (which also attempts to characterize state-level public land tagging in multiple states, including California), see United_States/Public_lands, which links to the Protected Area Database of the United States (PAD-US) maintained by the United States Geological Survey.
History
California Historical Landmark:
historic=heritage heritage=2 heritage:operator=chisl heritage:operator:wikidata=Q2933979 heritage:ref=### ref:chisl=###
California Points of Historical Interest:
historic=heritage heritage=4 heritage:operator=cphi heritage:operator:wikidata=Q16152996 heritage:ref=### ref:cphi=###
Historic El Camino Real is marked by a bell and sign mounted on the same pole. You can map both the bell and the sign as separate, coincident nodes.
Historic road bridges are marked by a special cream-colored sign.