United States/Road signs

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Flag of United States Part of United States mapping project.

Standard signs

The traffic_sign=* tag is optionally set to an ISO 3166 country code followed by a specific sign code. The source for most sign codes in the U.S. is the Federal Highway Administration's Manual on Uniform Traffic Control Devices (MUTCD). The designs are detailed in a separate document, Standard Highway Signs and Markings (SHSD).

Unlike in other countries, the national standard is not mandatory nationwide. Several states substitute their own state-level MUTCD standards; many other states supplement the MUTCD with state standards. Regardless, in a given state, most sign codes match the national standard. State-specific sign codes represent at most a small fraction of the signs in a given state.

Refer to the MUTCD field guide for the standard code for an unfamiliar road sign you see in street-level imagery, as well as suggestions on how to tag the infrastructure, advisory, or regulation that it indicates.

Route shields

Route shields figure prominently in the U.S. driving experience.

In the U.S., motorists navigate long distances using panoply of official but decentralized route marking schemes, or networks (network=*). Routes and their markers, or route shields, are designated by a variety of state and local transportation agencies and toll road operators. Route shields usually bear an unprefixed route number (ref=*) inscribed within a symbol. Unlike other kinds of road signs, route shields assume the motorist recognizes each symbol and is aware of the differences between each network. Networks often have conflicting numbering schemes, so it is important for software to identify routes using accurate symbols instead of making generalizations.

The most well-known shields belong to the following networks:

In addition, some states have multiple state route networks, county route networks in every county, or an extensive network of toll roads with special shields. If you encounter an unfamiliar shield in street-level imagery, consult the route shield field guide to determine the correct tags for the relevant ways and relation.

Traditionally, road atlases and online maps have relied on generic shields to simplify the user experience: for example, a state route always looks like 7 and a county route always looks like 157. However, these generalizations can be counterproductive depending on the use case.

Route shields are typically accompanied by a cardinal direction indicating which of the route's termini one side of the road leads toward. The cardinal direction is indicated used by navigation software but not by rendered maps.

Implementations

Renderer Debuted Relations Concurrencies Recognizable shields Notes
Interstates U.S. Routes State County Others
Magic Earth
?
?
yes yes yes no no N/A
Mapbox Streets 2015 no Only within a network yes yes Generic no N/A
Mapbox Leaflet 2014 no no yes yes Generic no N/A
Mapbox Navigation SDK 2017 N/A yes yes yes yes Generic N/A Displays shields in UI based on destination:ref=*
MapQuest Open 2010 no yes yes yes yes no N/A Discontinued in 2015
MAPS.ME 2017 yes yes yes yes no no N/A
Mapzen house styles[1] 2016 no no yes yes yes no N/A
OpenStreetMap Americana 2022 yes yes yes yes yes yes Various toll roads Lays out concurrencies of up to six routes along the road
Organic Maps 2021 yes yes yes yes no no N/A
OsmAnd 2016 yes yes yes yes yes Generic N/A Combines relation-based shields with way-based shields
osm-shields (Phil Gold) 2012 yes yes yes yes yes partial Various toll roads, townships Hosted by OSMUS from 2013 to 2021; prerenders combinations of shields in multiple orientations; see Wayback Machine, SotMUS 2013 talk
osm-shields (Kevin Kenny) 2018 yes yes yes yes yes partial Various toll roads, townships Forked with more solid technical foundation; clusters concurrencies in a grid to avoid prerendering
Overlay by Richard Weait 2010 yes partial yes yes yes
?
Historic 66 Transparent overlay atop openstreetmap-carto; see SotM 2011 talk
Stamen Terrain 2011 yes no yes yes CA only no N/A Optimizes shield positioning using Skeletron
TopOSM 2009 no no yes yes MA only no N/A

Route shield image assets have been made available for reuse in software projects:

The following renderers currently do not support route shields:

Bike Routes

Main article: Cycle routes#United States

See also