The Trouble with Trunk Roads

itsafrogslife · December 9, 2020, 2:34pm

I was wondering why some of the main roads in Liverpool weren’t appearing in the list of completed or uncompleted streets. When I looked on OSM I saw they are all added as Trunk Roads and that the ‘Allowed Access’ field has ‘Foot’ = ‘Not Specified’ (by default?). I guess that’s because you can’t assume that a trunk road has a footpath.

What it means, however, is that I’m going to have to do a hell of a lot of editing to change the acccess to “Foot” = “Yes” for all those roads I know are most definitely runable using a path or pavement.

Has anyone else found the same?

ericjrw · December 9, 2020, 4:11pm

I wonder if OSM allows for scripted, i.e automated (perhaps via SQL) edits? Might be a question for the Slack group - osmus.slack.com

mcoleman38 · December 9, 2020, 7:30pm

Hi Graham, this entry About the Node, Street, and City Data has a section on streets and in there you’ll find a link to a description of the query that is used to determine what to include from the OSM data. Checking that out will tell you what it is about certain roads that is leading to them not being included.

8f7162110d9eeaf907ab · December 9, 2020, 9:08pm

Trunk roads are excluded via the query since in most countries these are “car only” type roads. The UK has all A roads mapped as highway = trunk (see here https://wiki.openstreetmap.org/wiki/Tag:highway%3Dtrunk), which includes roads that go pretty deep into cities like the one from your example. Unless the query is altered, changing the foot permissions won’t make a difference so not much point going down that route, unfortunately. The “good” news is that it’s not that many streets: https://overpass-turbo.eu/s/111l

itsafrogslife · December 10, 2020, 5:19pm

Thanks for the info. Unfortunately in Liverpool the “good” news isn’t that good for me given that there are quite a few trunk roads, including those in the city centre on my screenshot and Queens Drive ring road which has housing along the majority of its length. I’m going to run them all anyway (why wouldn’t I?), it’s just a shame they’re not counted on CS.

ian · April 7, 2021, 10:53am

Hi @JamesChevalier,

I’m afraid that this is not correct:

The UK has all A roads mapped as highway = trunk

Per the link you gave, only primary A road (green signs) are tagged as such.

Many UK trunk roads in the UK are very much not ‘car only’. This is a few hundred metres from my house:

Is tagged as trunk on OSM (rightly per the guidelines) but is most definitely runnable, it has a pavement/sidewalk on one side. Could the import query not be modified to include roads like this please?

itsafrogslife · April 6, 2021, 9:01pm

I would very much like this!

m_l_heywood · April 6, 2021, 9:18pm

Its a difficult one this. I had the opposite issue recently where a mapping site I was using was insisting on using a dual carriageway as is was foot=Not Specified so I had to switch this road to foot=no to get sensible route suggestions.

Therefore, simply switching on trunk roads may give too many false positives. Would the solution therfore be to allow trunk roads but exclude foot=not specified? Would need to do the work suggested earlier in the thread to update OSM to be foot=yes but that feels the “right” solution to me.

As examples, both correctly tagged as Trunk in OSM

foot=no as I have updated as no paths

currently foot=not specified but footpaths both sides of the road (if I ever go for a run when back over at parents would update this to foot=yes)