[Tagging] Feature Proposal - RFC - junction=intersection

Matthew Woehlke mwoehlke.floss at gmail.com
Fri Jul 10 17:02:28 UTC 2020

On 10/07/2020 12.22, Clifford Snow wrote:
> Interesting suggestion. The sumo github page doesn't appear to have any
> open issues that involve OSM and intersections that I could find. (I only
> looked at intersection issue titles) Has this been reported to the sumo
> developers? Sumo documentation does suggest fixing OSM issues but other
> than that it seems to indicate that OSM data is suitable for use with their
> software.

I haven't reported anything yet, but (obviously?) it is my intention if 
this gains any traction to improve SUMO to automatically merge 
intersections based on this tag. That said, if you watch their 
*tutorial* (it's over an hour long), there is at least one example where 
the presenter shows an instance of this issue, so it *is* known to the 
community. I'm not sure if anyone else has had the idea to specifically 
annotate these in OSM in order to be able to better fix up such 
intersections automatically.

For my specific use case, it's moderately important to be able to 
convert OSM data into SUMO networks in a fully automated and 
deterministic manner.

Another issue, that isn't really OSM's fault, is that SUMO likes to add 
intersections wherever a way is split, even though only two edges come 
together. I don't think OSM needs to change anything there, however, 
except perhaps that it might be desirable to mark nodes where a U-turn 
is specifically legal.

> You mention that the duplicate traffic signals are a problem but I don't
> understand from your proposal how traffic signals should be tagged in your
> proposal. Could you update your proposal to include how they are to be
> tagged as part of the intersection.

That's because the proposal isn't proposing to change how signals are 
tagged. Rather, the objective is to make it so that "the existing way" 
("each [intersection] node is tagged as a traffic signal") Just Works™ 
with tools: "signals do not apply to a way which is tagged 

*Independently*, I am leaning toward suggesting to tag signals at the 
'stop here' line rather than on the intersection nodes (which also 
solves the signals aspect of the problem in a different manner), but IMO 
that is orthogonal. See e.g. 
https://www.openstreetmap.org/node/7695739446. (Also, if this proposal 
is approved, that change may or may not be necessary or desirable. I 
think the 'stop here' lines should be tagged in *some* manner, but with 
junction=intersection, it may be that a new way to tag 'stop here' lines 
is desired and leaving the signals on the intersection nodes is 
preferred. At that point, we're getting into arguing about tagging where 
the signal *applies* vs. where the actual signal lamp is physically 


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