The meaning of "Change highway tags to reflect real usage"

A view from the other side of the world:
The importance and classification of a road is based on the number of vehicles rather than the number of people using the road.
When I look at various street view pictures, I see 2 lanes and few vehicles including buses on Gawler Street. In contrast, Park Terrace has 4 or more lanes and many more vehicles (but of course no buses).
From a distance, it seems ok that Park Terrace gets a higher road classification than Gawler Street.

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if I can also clarify, when I was firstly looking into the information from Data SA I was lining it up one classification at a time rather than a whole. Tag:highway=secondary - OpenStreetMap Wiki The line being “highways which are not part of major routes, but nevertheless form a link in the national route network.” and “Secondary highways are generally specified by country road classification bylaws” together do match up with gawler street street being class as secondary, especially because gawler street handle thousands of bus and train commuters everyday. The one way road john street and the big shopping center have entrances from gawler street, there are government entities and doctors offices along gawler street as well, which adds to the traffic load. This was my reasoning for siding with the official data. I think both reasons are valid to be honest and I would like to find a middle ground somewhere, someone has mentioned to me that there is a another tag we can use that separates the “render” classification from the official. I think it would be good to still have the official data included. I accept your position on Gawler Street being as it currently is and would like to move forward. The major traffic route does not have to be trunk either, the roads can be changed to what they are “classed as” or “real usage” and the major traffic route can be tagged similar to route numbers so we dont lose that information either.

Not at all. And it seems like the replies to the thread below go a long way to answering this for you. I would just add that lots of frontages (shops, government entities and doctors) does not increase the classification of the road. In fact it likely decreases the classification. Consider motorways for example; they have no shops directly on them. Residential roads are full of active frontages (i.e. people’s homes and their driveways).

I mentioned the buildings because they add to the traffic flow, there is a cinema on gawler street as well, just trying to say that it is far from a quiet little street that you see by looking at imagery. I took the amount of traffic in consideration when weighing up the government classification at the time.

as fortura mentioned “heavily a road is used” is a criteria for the “real world usage” definition, I can assure you that it is very heavily used


What strikes me: There is a rule about access (although for truck it would be better to set hgv) and also all relations go the “right” way. That’s what routers need, isn’t it? So why is it so important to downgrade the OTG larger road? :thinking:

However Park Terrace is definitely used much more than Gawler Street.

if you have a look at the entrance to the bus terminal Way: 103971749 | OpenStreetMap there are currently 9 bus route that enter via gawler street, granted I have not look into how often these bus’s do their routes. This shows a very significant number of buses alone. the OSM Wiki definition of a Urban Tertiary road is as follow " Within larger urban settlements such as large towns or cities, tertiary roads link local centres of activity such as shops, schools, or suburbs. Use only for roads with low to moderate traffic. For the quietest sort of linking, non-residential road consider using highway=unclassified instead. For busier through routes and main roads use highway=secondary or greater." So I would just like to point out that Gawler Street may fall under the " For busier through routes and main roads use highway=secondary or greater." sentence as it is a very busy through route. However as I have said before I dont disagree with your classing it as Tertiary however there is a chance it may fall under the “busy through route” category.

I have to ask then, why did you originally change it from tertiary to secondary: Changeset: 141376507 | OpenStreetMap, then continue to fight over it since: OSM Deep History

because its fits the definition of Secondary by every single meaning as described here Tag:highway=trunk - OpenStreetMap Wiki and here Tag:highway=secondary - OpenStreetMap Wiki and it also being the “actual nature of the road” Australian Tagging Guidelines/Roads - OpenStreetMap Wiki , I dont disagree with it being classed as tertiary based on if there was no government data I would probably lean towards tertiary as well based on my own personal “ground knowledge”

very interesting discussion when you look at this from the other side of the world.

Normally, local mappers should agree on which classification a road should be given. It seems to me that this is not possible in your case. Hence my view from very far away …

What is the source of your figures?
How many of them travel by bus, bike or car? How many walk?
But I already wrote that the number of passengers doesn’t really matter. At least 10 times more passengers fit on a bus than in a car. Sure, a large proportion of passengers use the car. If I have seen it correctly, there are three large P+R car parks: two to the west site of the railway line and only one to the east, accessible via Gawler Street.

This ist a wish - and the other side is the real usage.

Wiki says:

Note that highway=* distinguishes roads by function and importance rather by their physical characteristic and legal classification. Usually these things are highly correlated, but OSM is not obligated to copy official road classifications.

In my opinion, four points should be assessed:

  • physical characteristics
  • importance
  • function
  • official classification

Physical characteristics:
In my eyes, Gawler Street looks like a typical unclassified in urban area with shops and a cinema. I see narrow lanes, pedestrian crossings (zebra) and some cycle lanes. This rather speaks in favour of a lower classification like unclassified.
It has already been upgraded to tertiary, which I think is right. Because:

The importance:
Gawler Street is an important collector street and serves as a feeder road to the shops/shopping centre, cinema and railway station. (see here)

It seems to me that Gawler Street connects the shopping centre and the railway station (a local area) to the road network, but it is not a major thoroughfare connecting neighbourhoods.

Official classification (is just one point among several):
Park Terrace is a road that is maintained by Department for Infrastucture and Transport (SA) - and I think SA means South Australia and not Salisbury :wink:
Gawler Street is maintained by the City of Salisbury.

Considering all four points and in comparison to the road network as a whole, I think the classification as tertiary is correct.

whats the source? The LocationSAMapViewer hat I found?
Is this a valid source?
There is no roundabout on Gawler Street.

And this dead end Winzor Place is a secondary?

Do you understand why I doubt that Gawler Street is correctly classified there? Official data doesn’t always have to be correct.

Or: I believe that this MapViewer does not visually distinguish between tertiary and secondary, as OSM does.


My last reply to fizzie I have said that I agree that it is a tertiary road.

the location viewer is a visual representation of the data from Data SA, Map Viewers and Portals | Data.SA you have to turn on the “Roads” dataset then click on the road to get the information of the road. I would personally match it up with the SHP file from here to be sure Roads - Dataset - from experience location sa and the SHP file match up entirely.

also if I can just say that the whole intention of this post is to have a constructive discussion so we can get something written down on what “Real Usage” means by definition as it is not recorded anywhere on the OSM wiki. We want to avoid random validators determining the classification of roads such as this example Changeset: 145314458 | OpenStreetMap , im sorry for saying this but it seems like people have a misunderstanding is all. All I have done is (with references) provided information from my point of view as to why I agreed with Data SA at the time.

That changeset didn’t involve any kind of validator/QA tool. If you think OSMCha is that, it’s not, it’s simply a utility that allows you to easily view changesets that match certain filters.

Also, just to point out, your original post was very focused on one specific road, so people are likely going to focus on that when reading/replying to it.

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yes it is because by focusing one 1 changeset it can be used as an example for all other “real usage” changesets.

I know what OSMCHA is I have used it for a long time I did not mention OSMCha. I just want to avoid situations like that in the future is all I meant sorry.

You mentioned validators on a changeset of mine that didn’t involve any. The closest there was OSMCha and you’ve called it one before in changeset comments.

I am sorry if I misspoke, just want to avoid changesets like that in the future is all.

Fine! This is exactly the definition that Wiki means by “real usage”: based on your own personal knowledge (in addition: considering all four points mentioned physical characteristics, importance, function and official classification and weighing them up against each other)

And: if different users in the same area come to different conclusions, then sit down together, compare your considerations and perhaps get some advice from external mapping colleagues.

I’ve seen some other road classifications in and around Adelaide that don’t seem conclusive to me.

One of my basic principles of thought: The road classifications (tertiary, secondary and primary) in OSM should never just end at roads of lower classification (there are very very rare exceptions), but always connect to the same or higher classified roads.


I just re-read this whole thread and just want to clarify that OSMCHA is and has always been referred to as a validator tool which is why I call it a validator regardless of what actions you take using it. Here is a example of a developer referring to it as a validator tool The state of OSMCha | OpenStreetMap US