Proposal:Make cycleway:both the default to indicate both sides

Make cycleway:both=* the default to indicate both sides
Proposal status:	Draft (under way)
Proposed by:	tordans
Tagging:	cycleway:both=* Data item
Applies to:
Definition:	Make cycleway:both=* the recommended default to indicate that the value applies to both sides.
Statistics:
Draft started:	2024-06-30

Proposal

Make cycleway:both=* the recommended default on highways to indicate that the value applies to both sides of a way. The recommendation should be followed when the mapper is able to clearly specify the bicycle infrastructure for both sides.

The definition of cycleway=* is not changed by this proposal.

This change only applies to values usually applied to one or more sides of a highway. Values like cycleway=crossing will continue to use the tag without any side subkey.

Rationale

The tagging of separate values for each side of a way is well established with side subkeys like cycleway:left=* and cycleway:right=*. However, the tagging of bicycle infrastructure that is present on both sides of a way is less clear. This leaves mappers and data consumers in a situation where the definition of cycleway=* (no side subkey) is unclear:

• It could mean "a cycleway somewhere on the way."
• It could mean "a cycleway on the primary direction of the way" with special treatment for cases like dual carriageway, oneway streets and/or oneway=-1 streets and based on the country (left-/right-hand-traffic).
• It could mean "a cycleway on both sides of the way."

The status quo leaves us with different interpretations on how to treat cycleway=*.

Therefore, we should make an effort to migrate cycleway=* to cycleway:both=* or its corresponding left and right tags to clarify the bicycle infrastructure.

This proposal does not seek to change the current definition of the tag, but rather to outline the existing interpretations.

Current Usage

Looking at some Editors

• StreetComplete treats the cycleway tag as the same as cycleway:both but tags cycleway:both. There are additional conditions for oneway=yes and oneway=-1 which westnordost explains in his forum comment.
• iD Editor only supports cycleway and hides all data tagged as cycleway:both. It presents the cycleway tag in a UI that shows it as left/right and merges left/right values into cycleway if the same values are tagged.

This discrepancy between StreetComplete and iD alone is why it is worth improving the current tagging recommendations.

Looking at the Wiki

• The wiki page Key:cycleway does not discuss sides in detail and does not mention the issue described here.
• The wiki page Key:cycleway:both discusses the ambiguity of cycleway.

Looking at numbers

Please keep in mind that those numbers can only be a signal for our opinion forming process.

They are heavily influenced by historic usage and editor presets.

• Historically the Key:cycleway was used. Usage of the Key:cycleway:both started around 2018 (Usage Graph). This favors the Key:cycleway in total numbers.
• StreetComplete is likely the driver behind a high number and increase of the cycleway:both=no value. This favors this key and the :both variant in general in total numbers.
• iD Editor: iD on the other hand only shows and tags the cycleway=* tag, even though mappers make a explicit choice per side. This favors the cycleway=* tags in total number even in recent years.

Of those distorting factors only the historic usage can easily be worked around by looking at usage in recent years in the usage graphs. More on that in the "Note" column below.

Value	cycleway=… from 2024-07 Taginfo	cycleway:both=… from 2024-07 Taginfo	Graph	Note
Sum	781.319 ways	1.464.887 ways	Usage Graph	The total numbers show the :both variant has the most usage overall but those number differ per value. The rows below look into each value and their grows trajectory in recent years.
no	296.789 ways	1.342.256 ways	Usage Graph	The graph strong increase of :both after 2021
separate	22.159 ways	27.019 ways	Usage Graph	The graph shows more :both since end of 2023. Please note that in the case of "separate," left/right indications are also an important piece of information for data analyses, data processing, and validation tasks and should therefore always be included.
lane	307.870 ways	64.212 ways	Usage Graph	cycleway=lane dropped mid 2022 and did not grow relevantly since then. The :both has less usage but shows a clear grows trajectory.
track	73.770 ways	11.607 ways	Usage Graph	cycleway=track is dropping continously since 2018. The :both has less usage but shows a clear grows trajectory.
shared_lane	76.652 ways	18.935 ways	Usage Graph	The graph shows both variants show a grows path with the non-both-variante having higher numbers.
share_busway	4.079 ways	858 ways	Usage Graph	cycleway=share_busway is a flat line since 2018 with a big jump in 2022. The :both has less usage but shows a clear grows trajectory.
Values without a left/right concept
crossing	149.498 ways	0 ways		Crossing does have concept of left/right, which is why it will continue to use the cycleway=crossing tag.
(and others…)

Also keep in mind that given that the cycleway-key is used for tags like cycleway=crossing and cycleway=asl we cannot compare numbers on key-level but have to sum them manually.

The wiki page on cycleway:both has a bit of history on the tag:

The tag has been in use since 2010.

Its usage has significantly increased in 2017 when it became used by StreetComplete which started asking about cycleways(…).

Definition

Key	Defintion
cycleway:both=*	The given bicycle infrastructure is present on both sides of the road.
cycleway=*	This proposal does not seek to change the current definition of the tag. However it is helpful to clarify the most common interpretation that can be distilled from the discussion around this proposal: The given bicycle infrastructure is present on the customary direction of the way. For a typical two lane forward/backward road, that would be bicycle infrastructure on both sides. For a oneway=yes road, that would be bicycle infrastructure on the customary direction of the road. (Given that no other tags say otherwise.)

Consequences

Documentation:

• Update relevant Wiki pages (like Key:cycleway and Key:cycleway:both) and Wikidata Items to reflect the updated recommendation and definitions.

Editors:

• Ask OSM editors to use the :both version whenever they provide an Interface to users that allows to clearly specify the cycleway for both sides. Examples of this would be iD, Rapid and StreetComplete. Ideally those editors will recognize both version but use the :both version when tags are added or modified, providing a soft migration path to the more precise tag.
• Ask OSM editors to consider adding feature that would allow for a faster update path to the more precise tag. An Example of this would be a tag update notice in the iD.

Rendering:

• Common rendering already supports both tag variations. However they might not all follow the same interpretation when combined with oneway=yes and edge cases like oneway=-1 that are related to this.

External discussions

• This proposal was created after discussions and deliberations in the Verkehrswende-Meetup.
• It was also inspired by work on the Radverkehrsatlas project.
• There was some discussion on an id-tagging-schema issue: https://github.com/openstreetmap/id-tagging-schema/issues/1025.
• There is a detailed discussion in the RFC Thread in the forum.

Comments

Please comment on the community forum page.