United States/Road classification
 Part of United States mapping project.
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The guidelines in this articles have been superseded by 2021 Highway Classification Guidance. As such, this page no longer represents a national consensus based on recent discussions on talk-us and the OSMUS Slack. When editing highway classifications in the United States, please consult state-specific documentation. |
--List--
This list is the base for US road classification. It is based off the US administative system already in place with minor modifications for trunk class and urban areas. Any state, or city clarifications should be noted on their apropriate page.
These are only rough guidelines, not rules. There is wide variation between the states as to how they designate routes, so take any route-based guidance below with a grain of salt. There are downsides to systematically under- or overclassifying roads in a given region. Road classification affects real people using OSM data in the field today, so please discuss any large-scale changes with the local mapping community beforehand.
Motorway
- Interstate Highways
- Freeway
- A Divided highway that is entirely grade separated.
- Short sections of grade separated, divided highway that are not connected to a regional network of grade separated, divided highways should probably have the same classification as the highway they are part of. This may differ from the classification implied by AASHTO or FHWA (AASHTO/FHWA standards are only able to imply the classifications for OSM roads as they do not have any authority over OSM).
Trunk
Unless part of the "Interstate system"
- A high speed Arterial Divided highway that is partially grade separated.
Primary
Unless classified as "Trunk or higher"
- Interstate Business Routes
- US Routes
- US Business routes
- State Routes in dense urban areas.
Secondary
Unless classified as "Primary or higher"
- State Routes
- State Business routes
- Major Urban Streets = Streets in Urban areas with high amount of traffic, usually lined with businesses and controlled with traffic lights. (Often roads that cross highways and rivers)
Tertiary
Unless classified as "Secondary or higher"
Residential
Unless classified as "Tertiary or higher"
- Minor Roads in residential areas.
Unclassified
Unless classified as "Residential or higher"
- Minor Roads.
Service
- Alley, Driveway, Parking_aisle, other service