Major road and rail planning schemes typically take years until actual construction begins. We may therefore wish to show planned roads, railways, routes (airports, other features...) on the map. Some commercial mapping companies also show planned features. This key can be used for any feature that is still in planning phase but construction hasn't yet started. For features under construction use construction=* instead.
In many cases it may be preferable to use a lifecycle prefix such as proposed:leisure=playground.
The way to tag planned features is to use the main tag (Key, e.g. highway, railway, amenity, aeroway, ...) and add proposed as value. Then you create another tag proposed=* with x being the <value you usually would put on the main tag>.
You are also encouraged to add the source for the plan with source=*. Please take care about copyright issues and don't copy from plans you're not entitled to do so.
Values of proposed=* can be all values usually used for the key where you inserted proposed as value (see above). Please keep in mind that cluttering the editors will cause problems (payload, clutter) to the other mappers, so don't exaggerate with proposed features.
|motorway_link||proposed motorway sliproad|
|trunk||proposed important non-motorway road|
|trunk_link||proposed sliproad to an important non-motorway road|
|primary||proposed primary road|
|primary_link||proposed sliproad to a primary road|
|secondary||proposed secondary road|
|tertiary||proposed tertiary road|
|unclassified||proposed unclassified road (alternatively tag <proposed=minor>)|
|residential||proposed residential road|
|pedestrian||proposed pedestrianised road|
|service||proposed service road|
|footway||proposed foot path (alternative tag <proposed=footpath>)|
For roads to be removed, use proposed:highway=no. This is understood by (at least) ITO's Transport Construction map.
The way could be rendered as a modified (dashed, dotted, etc.) version of the corresponding <highway=.....> tag. See the highway tag for a full description of the rendering style.
|rail||proposed standard gauge railway|
|narrow_gauge||proposed narrow gauge railway|
|preserved||proposed preserved railway|
The way will usually render as a modified version (dashed, dotted, etc.) of the corresponding <railway=.....> tag. See the railway=* tag for a full description of the rendering style.
For more specific description of the planning phase it would be necessary to invent an additional tag, because not all plans are realized, hence describing the probability for a proposed project to be realized. Please add documentation here in the future.
- a further tag could be added to illustrate the expected beginning of construction and planned opening date.
This is frequently used to describe projects that are abandoned, planned to start in a distant future and ones that are de facto fictional. See https://github.com/gravitystorm/openstreetmap-carto/issues/908 for examples.