Proposal:Extended expressway tagging

Extended expressway tagging
Proposal status:	Draft (under way)
Proposed by:	ZLima12
Tagging:	expressway=limited, expressway=controlled Data item
Applies to:
Definition:	Whether a road is physically an expressway
Statistics:
Draft started:	2025-10-24

Proposal

The word "expressway" can be used to refer to two different kinds of high-speed roads: either a limited-access highway or a controlled-access one. Currently, the expressway=yes tag is used in OSM to describe a road as the former, limited-access meaning. I am proposing that we extend the expressway=* key to be able to describe both meanings of the word expressway, either limited-access or controlled-access. Two new values of the key will be understood:

• expressway=limited: This may be used to describe limited-access expressways, like the current expressway=yes.
• expressway=controlled: This may be used to describe controlled-access expressways, also referred to as freeways or motorways.

This proposal is strictly concerned with the physical characteristics of the road, like the current expressway=yes is. In contrast, highway=motorway is associated with specific legal classifications in some countries, in addition to having certain expected performance characteristics. Most highways currently tagged as highway=motorway will not be altered as a result of this proposal; that tag will now imply expressway=controlled, which is correct in most places. Nonetheless, this implication may be overridden with expressway=limited when applicable, and expressway=controlled may be used on roads that meet the performance requirements but can not be classified as highway=motorway for region-specific reasons.

Should this proposal pass, there will be a grace period of 9 months in which the expressway=limited and expressway=controlled tags should not be used. This is to give data consumers a chance to update their software to understand the new tag. After the grace period ends, most roads previously tagged as expressway=yes may be tagged as expressway=limited instead. However, this should be done on a case-by-case basis; no mechanical edit shall be performed to do this retagging.

At a minimum, consumers should begin to interpret any value of expressway=* that they do not understand (other than expressway=no) as expressway=yes. Assuming no other changes to the software are made, roads that were previously tagged as expressway=yes and retagged to either expressway=limited or expressway=controlled will be treated exactly as they previously were. As an added benefit, if a new value to expressway=* is added in the future, consumers that do not yet understand the value will still treat the road as "some kind" of expressway (see #expressway=yes). Of course, consumers are encouraged to add support for each value of expressway=* to better understand the type of road in question.

Rationale

The expressway=yes tag has proved useful to identify high-performance roads independently of their classification/importance (highway=*). Depending on the region, highway=trunk has been used to describe limited-access expressways, but in recent years there have been efforts to decouple performance characteristics from this tag. This has been quite beneficial, as it is not uncommon for limited-access expressways to only be as important as a highway=primary, or occasionally highway=secondary and lower.

While it is somewhat less common than the previous situation, sometimes a controlled-access expressway is not important enough or otherwise does not meet regional requirements to be a highway=motorway. However, there is currently no good way to convey that a road is a controlled-access expressway other than the highway=motorway tag. This is the primary issue that this proposal seeks to address; by using the expressway=controlled tag, the physical characteristics of the road can be properly conveyed while using any highway=* value.

motorway=yes has previously been proposed to serve the same function as expressway=controlled, but the current proposal has a few advantages:

• motorway=yes currently has a different meaning, pertaining to legal restrictions
• Similarly, the word "motorway" has associations with specific legal classifications in some regions, most notably the UK where the term originates from
• General confusion between highway=motorway and motorway=yes
• expressway=* is already being used to describe physical highway construction

Tagging

highway=motorway

highway=motorway should continue to be used on roads that match the relevant legal criteria in the region, or those that meet the requirements decided on by the region's mappers. highway=motorway will now imply expressway=controlled, so it is recommended to not use any expressway=* tag in most cases. However, in rare cases where a road that should be highway=motorway is not fully controlled-access or otherwise does not meet the requirements for expressway=controlled, this implication may be overridden with expressway=limited or even expressway=no.

expressway=no

This tag will remain unchanged.

expressway=limited

This tag will be used in mostly the same way as expressway=yes has been, but it will also explicitly mean that the performance of the road is less than that of a expressway=controlled. As such, expressway=limited can be used on highway=motorways (in rare cases) to convey that despite meeting local requirements for motorway, the road is not a full expressway=controlled. Roads tagged as expressway=limited must have a higher than usual maxspeed=* and accompanying design features, and meet one of the two following conditions:

• dual_carriageway=yes (Divided highway) + access_control=partial (Limited-access)
• access_control=full (Fully controlled access)

expressway=limited may also be used occasionally on roads that are fully controlled-access (access_control=full), but are significantly below the region's standards for expressway=controlled. For example, the on/off ramps to the highway might be very short, turn at near 90 degree angles, and/or have stop signs on them. The main roadway may also have tighter turns, narrow or no shoulders, and a lower overall average speed.

expressway=controlled

Use this tag on highways that are not highway=motorway but are controlled-access expressways. This tag implies at least the same physical characteristics that highway=motorway has historically, but does not imply any legal restrictions. To say that a highway has the same legal restrictions as a motorway, use motorway=yes instead. The exact level of performance that is required for this tag may vary slightly by region, but roads with this tag must meet the following characteristics:

• Everything required by expressway=limited
• access_control=full: No intersections, all access via link roads/ramps
• lanes=2 or greater per side of traffic

expressway=yes

Now that we can describe both kinds of expressways, expressway=yes will become ambiguous. It will now mean that the road in question is at least expressway=limited, but it may also deserve expressway=controlled. Mappers are encouraged to use one of the two more specific tags, but expressway=yes may be added if there is no expressway=* tag already and it is unclear which of the two is appropriate.

Examples

Just highway=motorway

• M1 motorway
• Interstate 80
• Bundesautobahn 2

highway=motorway + expressway=limited

Roads that are legally classified as a motorway but are not fully controlled-access. Anyone may insert examples here if they know of one.

expressway=limited + access_control=full

Roads that are fully controlled-access, but are significantly below typical controlled-access expressway performance.

highway=primary + expressway=controlled

This list is US-centric, so please add examples from other countries if you know of any.

• LaSalle Expressway
• Part of Lake Ontario State Parkway
• The currently highway=motorway part of New Mexico State Road 423
• West Bend Freeway (US-45)
• Potentially Ontario Highway 406 and Ontario Highway 58
• A portion of Desert Inn Road

Comments

Please comment on the discussion page.