Proposed features/motorway junction Extension

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highway=motorway_junction Tagging Extension
Status: Abandoned (inactive)
Proposed by: rickmastfan67
Tagging: highway=motorway_junction
Applies to: node
Definition: Extension of the "ref" and "exit_to" sub-tags that work with "highway=motorway_junction"
Rendered as: same way as it is currently
Drafted on: 2011-05-22
RFC start: 2011-05-22


The reason this is being proposed is to aid in tagging of highway exits that have ramps that split after they leave the mainline of the highway. Most of the time, they will only need the "exit_to:right=*" & "exit_to:left=*" part, but sometimes they do have a split exit number (see "real life examples" section) when the exit splits into two separate ramps (hence the "ref:right=*" & "ref:left=*"). Thus the reason for this proposal.


This is needed to help deal with split ramps where the router can't always display the correct info of where each ramp goes which frequently happens when exit ramps split. Most of the time, they guess and they are sometimes wrong. This would especially help when displaying mapping directions on a website (like MapQuest Open) if they are willing to accept this change and support it. This would allow us mappers to properly tag the exit number and the destination that are posted on the signs.


Some examples where this would need to come into play are when a highway ends and splits into two separate ramps (one for each direction of the highway it's intersecting). Some examples of that would be I-77's Southern end @ I-26. Several 3di's (3 digit Interstates) end @ T-interchanges with their parent Interstate (I-381, I-581, I-190(NY) + others) where the signs are obviously different for each direction (not all have exit numbers at said junctions, but the I-381 does).


Extended Tagging scheme for highway=motorway_junction
Tag Notes
Used on node
highway=motorway_junction (required)
This tag is for the exit number of the motorway_junction (exit). Currently, the "ref=*" is the default tag.
The "ref:right=*" & "ref:left=*" are to be used when encountered in split exit ramp configurations where each ramp is given it's own number.
As in current practice, "exit_to=*" will still be used for normal non-split exits.
"exit_to:right=*" & "exit_to:left=*" are used to tag ramps that split and go to different locations (per highway signage).
Optional - Only needed if the exit has a name. See example on highway=motorway_junction page.
"name:right=*" & "name:left=*" to be used only on split junctions where each side has different names in the same way the normal "name=*" tag is used here.

Applies to

Only applies to node's.


When rendering a split exit, all renders should "merge" the two tags together to render like this "1B-1C" if base "ref" tag isn't present.
When rendered: 1B-1C
This could also be accomplished by just manually tagging the two numbers in the default "ref" tag as so: ref=1B-1C.

Features/Pages affected


Real life examples

  • node 684996085 - Exits #1B-1C on I-279 in Pittsburgh, PA, USA.

Additional uses

This could also be used when dealing with motorways that split off from another motorway (to the right or left) and both ways are tagged with highway=motorway. In those cases, you could use the *:right/*:left tags to let people (data users) know which highway is considered to be the *exit* and which is the mainline in their directions. Three such examples would be the following:
I-279 splitting off of I-79. Would use the exit_to:left=* & ref:left=* tags.
I-579 splitting off of I-279. Would use the exit_to:right=* & ref:right=* tags.
I-74 splitting off of I-77 (this one is an example of the two sharing the same highway and then splitting). Would use the exit_to:left=* & ref:left=* tags.


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