In July 2023, @dieterdreist replaced the original text “Too narrow” with “Illegal for motor vehicles” in the top right cell. The original text tried to contrast this case with “Narrow” in the top left and “Wide enough but illegal” in the bottom right. Would anyone oppose reverting this change? Or perhaps improving the description?
@dieterdreist, I am guessing the picture is this way which was previously tagged as highway=footway and you changed it to service=alley, presumably because it’s legal for motorcycles?
yes that’s correct, I also checked with the Italian community on Telegram before I changed it, likely more footways there are actually alleys but I didn’t check it, also the names were mostly missing so I guess these are aerial tracing
Is this case common in Italy? I mean, is this example representative of service=alley?
Or are most cases of service=alley e.g. here in Rome wide enough for cars?
I would not be astonished if there were alleys in Rome which are not wide enough for cars, but I am not sure (the historic center is restricted traffic area anyway), generally these are much more to be expected in rural areas with medieval centers, the less tourists they get, the laxer the regulations and fewer the signs, in remote villages you can drive wherever physically possible with your vehicle, but many alleys may not be wide enough to fit your car
Most are wide enough for cars. Expand the Rome table in this study of the existing data I did a while ago.
Frankly this study is not useful from my point of view, because this is not a phenomenon to be expected in metropolitan areas such as
Greater London Espandi
These have mostly lost their medieval core, so they are not representative for narrow medieval alleys. Maybe Edinburgh or Rome are exceptions, NYC never has medieval settlements, Berlin destroyed the rest after the last war, …
Also these big cities already were big cities with wider streets when in small remote places narrow alleys seemed sufficient or advantageous.
To me, using service=alley for old medieval streets, as in the examples given so far, has always been related to the difficulty of passing due to the narrow width of the way. Where traffic is illegal it clearly cannot be service=alley or any type of highway=service, it must be a non-motorized type (pedestrian, footway or path), reflecting the intended primary use of the way. If it were about legality, then I cannot understand any of the uses of service=alley in Rome or any of the other cities I listed in my study, they would be mapped incorrectly from this perspective, as they are all allowed for wide motor vehicles like cars and many are narrow, but none are that narrow.
They would fall under the microcars category, as vehicles like ATVs, golf carts, and rickshaws each have their own distinct classifications.
I’ve previously was told that a trail wide enough for an ATV, but not for a 4WD, should be tagged as highway=path rather than highway=track. So, I’d like to clarify: what defines a minor road based on width? What makes sense to classify as a road versus a path on a map?
I’ve argued that using the passability of certain motor vehicles as a guideline isn’t effective, particularly because in many developing regions, pathways are often only accessible by motorcycles.
Would it make more sense to use a threshold of 1.5m instead of 2.0m to make this distinction?
The various different types of service road are basically sui generis from a routing and rendering point of view. A driveway is not a parking aisle is not an alley is not an emergency access. (Also, a service road in the US is not a service road in the UK is not a service road in Germany. Writing routers is fun.)
highway=alley would have been, and would still be, a good idea. It shouldn’t be a massive problem if that’s actually represented in the database as highway=service, service=alley, because any halfway competent router/renderer will already be parsing the service= values anyway.
We do, of course, know that many renderers are not halfway competent - hence the whole highway=scramble debate. So the challenge here is to find something that’s “less wrong”.
highway=footway is very wrong. It doesn’t have the typical physical characteristics of a footway and you’d have to reverse the access implications for motor vehicles, bikes, horses etc. etc. Experience suggests that people are usually a bit slapdash with this and tend to forget one or other class of access. So nope. Same for =cycleway and so on.
highway=path is a clusterf—k beyond all recognition and anyone still proposing using it in 2024 for anything other than informal paths needs their head examined.
highway=service with service=alley is not wrong but potentially a little ambiguous. An “alley” can be a narrow residential street like this. But it can also be a back-access to shops and houses, not really meant as a general-use thoroughfare but as a shared service route.
highway=residential with a maxwidth or width tag is also not wrong but possibly liable to misinterpretation. Routers will potentially ignore the width restriction (OSRM does enforce a minimum width in its default profile: I don’t know about Graphhopper or Valhalla). But then residential roads typically have the lowest weight for car routing so the effect here is perhaps less than it might be.
My gut feeling is residential+width tags is the least wrong and that parsing width tags is table stakes for a car router. But alley would not be a terrible outcome.
If we’re talking about alleys too narrow for most 4-wheel vehicles, that’s exactly what highway=path is meant for. The issue is that people who tag for the renderer don’t like seeing a natural trail appear the same as a concrete urban path.
No, a narrow residential street is still considered a residential road. If it’s too narrow for a typical car, it’s classified as a pathway, not a street or road. The issue was that mappers didn’t want to wait for renderers to support lane or width tags, so they used the controversial service=alley to make the roads appear smaller on the map.
Minor may be an official term somewhere, but I think in the wiki it means “of lesser socioeconomic/traffic¹ importance/significance”, but not necessarily narrower or smaller. The wiki says that highway=unclassifiedmight be distinguished by being narrower or by being a minor road, but it could be that some highway=unclassified ways are neither of these things.
At least in Brazil since 2020, rural highway=unclassified roads are those that lead to mostly empty or sparsely populated areas. As a result, they have very little traffic and are not prioritized by the government for improvement (signage, enlarging, paving, re-compaction, repair). So the observable characteristics are a consequence of the way being unimportant. But some of them, especially near major cities, are in better condition: they may be wider due to planning for the future expansion of those cities, and some are even paved. But they are still minor (less important) in a relative sense, compared to other ways in the same region.
¹ In Brazil, higher classification (tertiary, secondary, primary, trunk) is more strongly determined by socioeconomic importance in rural areas and by traffic/mobility in dense urban street meshes.
I try to avoid highway=path whenever possible as it is controversial and has little meaning, if you see a rendered highway=path you have almost no idea what to expect. When I come across a way that is clearly not intended for motor vehicle traffic and has no cycle way signage, I assume it is primarily intended for pedestrians. If it looks like a pedestrian street (it looks like other streets in the same area), I map it as highway=pedestrian. If not, then:
If it looks intentional/planned (it is built or at least well maintained, even if unpaved), I map it as highway=footway
If it looks unintentional (e.g. a dirt trail trodden by hikers on grass), I might map it as highway=path if it is in particularly poor condition (e.g. the grass is starting to take over, indicating that few people have been using the trail)
In a different context, highway=path may be used for a combined sidewalk-cycleway in case S3, but even in the similar case S4, we are encouraged to decide what the way is mainly, and the same is suggested as an alternative for case S3. (Here, perhaps controversially and to avoid experiencing mapper’s cognitive dissonance myself, I interpret case S5 as a cycleway with a sidewalk, so I map it as highway=cycleway+sidewalk=*).
That one is interesting anyway because if you look closely, you can see that kerb isn’t perfectly flush (slightly raised for the footway). For this reason, I think that a different image should be chosen as an example of a segregated foot- and cycleway (e.g. one which uses differently coloured paving stones for each mode).
highway=alley would have been, and would still be, a good idea. It shouldn’t be a massive problem if that’s actually represented in the database as highway=service, service=alley, because any halfway competent router/renderer will already be parsing the service= values anyway.
….
highway=service with service=alley is not wrong but potentially a little ambiguous. An “alley” can be a narrow residential street like this. But it can also be a back-access to shops and houses, not really meant as a general-use thoroughfare but as a shared service route.
I share the findings of your assessment and am willing to create a proposal for highway=alley (in a couple of days when I returned from traveling), but I also see some potential conflict/confusion with these different types of alleys (back access and narrow streets).
I’ve previously was told that a trail wide enough for an ATV, but not for a 4WD, should be tagged as highway=path rather than highway=track. So, I’d like to clarify: what defines a minor road based on width?
track is out of question because it is based on use rather than physical characteristics. highway=path can have many faces, its range is from hardly visibile paths in remote areas to cycleways in cities. Unfortunately, globally and in most places it was defined as defaulting to prohibit vehicular traffic thus almost inverting the default access=yes for generic highways, so that the application for generic roads gets into the direction of troll tagging
Roads only passably by small motor vehicle are NOT generic roads They are special cases.
I can understand that highway=path in developed countries can be seem as controversial, so I would welcome the creation of new highway tag to differentiate general urban narrow pathways accessible from nature/informal paths found in rural/outdoor areas.
Similar to highway=footway, with the difference that the new tag would legally be accessible by default by other small motorized and non-motorized vehicles.
However I would suggesting finding something else than “alley” which is already used with service=alley, footway=alley and would lead to further confusion.
Roads only passably by small motor vehicle are NOT generic roads They are special cases.
I agree these can be seen as special cases (hence the idea to use a dedicated class), but they are generic in the sense that there is no specific signage and therefore the normal road rules apply (as opposed to e.g. footway, living street, or pedestrian, where signs are required and special rules apply)
They are special cases.