South Australia - Major Traffic Route as Truck Roads

I would like to open a discussion here to try to come to a consensus about the Major Traffic Route in South Australia and if it should be kept as Trunk roads or not.

A discord discussion I had with ouchjars | OpenStreetMap lead to the Major Traffic Route in SA to be classed as Trunk Roads. The main reason it was done like that is because of tagging guidelines suggests it here Australian Tagging Guidelines/Roads - OpenStreetMap Wiki . Recently there have been classification changes to some of these roads which has removed the Trunk classification from the Major Traffic Route. I think in the long term we need to 1, either keep the major traffic route entirely trunk or 2 don’t use the Trunk classification at all for the metropolitan Major Traffic Route.

I would like to discuss this before anymore changes are made, Thankyou

Everything on that linked wiki page says that it should be based on the actual nature of the road, i.e. on the ground, and that the guidelines are a suggestion.

We shouldn’t be tagging roads purely for being part of a government grouping, and most of those roads on their own wouldn’t meet any guideline/suggestion for being a trunk road.

1 Like

A recent discussion that we had here The meaning of “Change highway tags to reflect real usage” - Communities / Oceania - OpenStreetMap Community Forum clearly indicates that “actual nature of the road” and “reflect real usage” and “whats on the ground” are 3 completely separate meanings.

if you’re saying it should be based on the “actual nature of the road” then you’re saying they should be kept as “trunk” right? because that is the actual nature of the road.

A discord discussion I had with ouchjars | OpenStreetMap lead to the Major Traffic Route in SA to be classed as Trunk Roads.

I was, and still am, against the notion that we have to copy road classification 1-to-1 from any source:

Data SA classifies roads in a way that doesn’t appear to neatly map on to OSM road heirarchy [me, 02/09/2023 23:08]

This was in reference to the first mass import you proposed, copying classifications from the Roads dataset. I pointed out inconsistencies in that data at the time, and it’s just been relitigated in your thread about Park Terrace and Gawler Street.

At most, I tentatively agreed with your proposal to classify all A roads as trunks, not the set of “Major Traffic Routes” designated in the Functional Hierarchy for South Australia’s Land Transport Network dataset.

The latter includes relatively minor roads like Fullarton Road and Richmond Road, but not e.g. Regency Road and Goodwood Road which are built to a higher standard and see equal or greater volumes of traffic (cf. Traffic Volumes dataset).

The former would be consistent with the Australian Tagging Guidelines as written, but now I have reservations about even doing that completely, as some A roads closely parallel other, more major A roads, e.g. Churchill Road/A22, Northcote Terrace, and Marion Road/A14.

1 Like

Just for your and everybody else reference here, I have not expressed an opinion either way with the subject of this thread at all. I am just asking for a consensus is all. Your reply comes across as combative. I think we can agree that a consensus has to be made so we can move forward in a uniform way. I was following the Trunk Road guidelines as I understood them at the time. I accept any outcome here.

Not only does that forum post never come to any kind of actual conclusion, but the actual nature of the road can (and from my experience with OSM, does) mean the on the ground usage.

I also in no way implied that they should be classed as trunk in any way, please don’t put words in the mouths of other mappers.

I have to 100% agree with @ouchjars as well, their post very much aligns with my thoughts.

1 Like

I in no way am putting any words in anybodys mouth, it was a question with a question mark given that “actual nature of the road” is exactly what the OSM wiki says I thought you were agreeing with it, “ground usage” means “what it looks like from the ground” I agree with ouchjars aswell. The difference is the process behind the decision to classify a road, I like the traffic volume dataset a lot, that may be helpful.

Datasets should be used to help supplement information we get on the ground, they shouldn’t be used to determine highway classifications solely.

If we don’t have any way to really see what a road is like, then it can be a good way to get a picture of what roads are like, but we shouldn’t be basing classifications off of datasets when we can look on the ground.

Things like names, speed limits, road surfaces, that’s great to fill in from datasets available for us to use, but classifications we can simply look at the road, and should.

why am I always being put in defensive mode, targeted attacks on me in all these threads. The DWG literally asked me to use this forum as intended if I am coming across as someone who has a decision made up thats on you. No where am I saying how I feel about the road classifications other than looking for a agreement.

I’m happy to speak for my experience with you as a mapper, in your first ever interaction and every interaction with me regarding changes, you’ve come in claiming vandalism or acting as if you are right and everyone else is wrong. Since receiving a ban, every discussion you’ve raised is always worded in a way that appears to lean to one way, the way that based on your edits and comments, is the way you favour.

If you want people to have these discussions and come to an agreement with you, please think about how you word things, come in as neutral as possible, and please show that you are listening to others opinions.

You have done that better in this thread than any other interaction I have been involved in with you, and I do greatly appreciate that and do want to thank you for that, but you’ve still come in with a forum post that reads as looking for agreement with one view, not an open discussion to come to a communal agreement.

I want to work with all mappers, but considering the history of interactions between myself and you, you cannot expect me to act as if we’re best buddies or anything like that at this stage.


I understand what you’re saying to be honest, When I say why they are like they are in the first place I explain my previous actions with reference the the OSM wiki as I personally understood them at the time. Im sorry if it come across as its the correct way as things are not so black and white. I am also a pretty experienced mapper having edited almost every square inch of SA by hand in ID. I think as people we are capable of reaching a consensus.

I do appreciate that, and with everything, people are going to sometimes have different interpretations, which is why we need to have discussions, but past interactions are going to impact how people present their opinions.

Back to the topic at hand, I don’t see actual nature specifically meaning from a government dataset or anything specific like that, it’s more about how we as mappers on OSM should be looking at something, which is looking at what it’s like on the ground. Going with that, the SAMTR is definitely one thing to help when determining at how busy roads are and how important roads are, but it shouldn’t be the be all and end all, and every road should be considered on it’s own merit.

I think the better way of thinking would be “this specific road is part of the SAMTR, so it’s likely going to be a higher classification, probably towards trunk or primary, and in a few edge cases it could be lower” rather than “roads in the SAMTR should be classified as trunk or primary”.

Information like this is great to help guide decisions for individual elements, we shouldn’t be doing it the other way round and trying to classify en masse because a road is part of the SAMTR or any other network.


I would consider a partial import of Roads - Dataset - for the lower end of the classification heirarchy. Currently we have a lot of suburbs flanked by trunk/primary/secondary roads with an undifferentiated mass of residentials/unclassifieds in the middle.

Going through areas I’m most familiar with in that dataset, I see roads tagged as “Collector” vs “Local” in a way that seems consistent with wiki guidance for highway=tertiary:

Use it for roads that either serve at this intermediate level or simply those that form a more developed or well-used link in the hierarchy than the most minor sort of street or lane if there’s not much planning or variation in the area you’re mapping.

We have discussed the case of Park Terrace, Salisbury, where “Collector” seems an inappropriately low classification, but I don’t see any cases of the opposite problem; i.e. I don’t (yet) see any issues if we use the “Collector” designations in that dataset to reclassify roads from residential/unclassified to tertiary.

Definitely worth having a look into, I’ll have a look around some areas I’m familiar with to compare and see what it looks like, there’s at least a couple of roads off the top of my head that do have collector roles that I’m pretty sure are classed as residential, not sure if the Roads dataset has them classed higher or not.

Plenty of Residential roads to fix - here is a good one to start with

Pulled the Roads dataset into QGIS, filtered down to roads classed as collector, and overlayed that over OSM, and had a look at some areas I’m pretty familiar with and a few other areas.

There’s definitely plenty of roads in there that I’d think would be better classed as tertiary, but there’s also some that I’d keep residential, especially where it looks like there’s been changes to roads, or a few spots where there’s a gap between two roads listed as collector, but that gap means one of them serves a very small number of properties. There’s definitely a few spots I’ve checked where it looks like a couple of segements of roads have been classed as collector to try and bridge two much larger collector roads.

Couple of examples of areas that I think would be good to take collector roads into OSM as tertiary:
This area in Old Reynella
This area in Woodville
This area near Montague/McIntyre/Nelson roads

And some that I think have a few slight issues:
This joining segments to the left of Hallett Cove School
This little segment in Morphett Vale

There’s definitely some roads in the filtered dataset that probably should stay residential/unclassified, and there’s definitely some that should be secondary considering the local area.

Now I’m gonna go figure out how to speed up the rendering in QGIS to make looking at this (and other data) a lot easier.

1 Like

save it as FlatGeobuf FlatGeobuf — GDAL documentation and then open that


Wow that’s a huge difference, immediate rendering even with the full dataset, thanks fellow Andrew!