User:Btwhite92/California Highway Tagging Guide

Work in progress

Classifying Highways

General Guidelines

The 'highway' tag is used to classify highways by their importance in the overall highway network. Other than motorway and trunk,

CA Highway Tagging Cheat Sheet

	Rural	Urban
Motorway	Freeways. Any highway that is: Physically divided Fully access controlled Singular grade-separated interchanges on highways that are otherwise tagged trunk should not be tagged as motorway.
Trunk	Expressways. Any highway with partial access control and relatively high speeds, often divided and with grade-separated interchanges. In California, these come in many different shapes and sizes - please see the guide below for more detailed information.
Primary	Major highways that connect large towns and cities, but are not built to freeway or expressway standards. This includes all US routes, many CA state routes (especially those in the Freeway & Expressway system), and occasional county routes. Physically, always at least a paved two-lane road that is passable year round, with end-to-end connection to other important highways (no spur roads!)	Continuation of any primary road entering an urban area, either through the urban area, or until it meets a highway of higher classification. Major urban arteries that perform a significant role in circulating traffic through a major part of an urban area that a freeway or expressway does not. Typically a state or county route, but not always. Many smaller cities will have none of these; larger cities, even in major metropolitan areas, will have only a handful.
Secondary	Minor highways that connect smaller towns and communities to more important roads. This includes many CA state routes, and most county routes. Physically, always at least a paved road, but may be subject to winter closures in regions with heavy snowfall.	Continuation of any secondary road entering an urban area, either through the urban area, or until it meets a highway of higher classification. Urban arteries. Main roads through a city, interfacing with the nearby freeway/expressway/primary highway system.
Tertiary	Rural collectors that connect very small towns or serve as a backbone road for dispersed residential areas. Physically, typically a paved two-lane road with higher speeds that other local roads. Unpaved through roads should typically be tagged as unclassified, unless (rarely) it is the only significant road for a decent population for tens of miles (example - Mendocino NFH 7 bridging the gap in CA 162).	Continuation of any tertiary road entering an urban area, either through the urban area, or until it meets a highway of higher classification. Urban collectors. Minor roads that collect traffic from local destinations and move it to more important roads.
Unclassified	Minor roads that provide circulation through rural areas. Physically, anywhere from a paved two-lane road to an ungraded dirt road in remote areas.	Continuation of any unclassified road entering an urban area, either through the urban area, or until it meets a highway of higher classification. Local roads used to access to non-residential areas. Typically found in industrial and commercial parks. Roads used to provide access on to or through a specific property (even large properties like malls) should be tagged service and not unclassified.
Residential	Local roads used to access residential areas. In rural areas, very often unpaved or even ungraded.

Motorway

Used for freeways. Any divided highway with full access control (no direct access to adjacent properties, access by ramps only, grade-separated interchanges) should be tagged as a motorway.

Examples include I 5, CA 210

Trunk

Used for expressways, though there is debate regarding this. The conventional MUTCD definition for an expressway is "a divided highway with partial access control". California defines expressways more generally as any highway with partial access control. In order of strongest to weakest, some forms of California expressway:

Primary

Rural

Used for major highways that provide the best route between important population centers throughout and beyond the state.