Recently, @Maro21 updated the service=alley wiki description to “A service road usually located between properties, sometimes too narrow for cars to access.” I reverted this change due the lack of prior discussion and conflicting definitions.
So, I’d like to continue the discussion from here: can a narrow way still be classified as a minor road if most cars cannot pass through it?
@dieterdreist provided an example of an alley in Italy with a maximum width of 1.70 meters.
Italy is known for its narrow medieval streets, limited parking, and many small cars on the market. According to this link, here are the best selling small cars and their width:
Fiat Panda: 1.67 meters
Fiat 500: 1.62 meters
Dacia Sandero: 1.76 meters
Lancia Ypsilon: 1.72 meters
Toyota Yaris Cross: 1.77 meters
Volkswagen T-Roc: 1.82 meters
Citroën C3: 1.75 meters
Ford Puma: 1.80 meters
Dacia Duster: 1.80 meters
Renault Captur: 1.80 meters
The width of a car typically doesn’t include mirrors. When folded, side mirrors add approximately 10 to 15 centimeters on each side, or about 5 to 7.5 centimeters per side.
Therefore, none of these commonly found vehicles could fit through such a narrow alley, except perhaps for tuk-tuks or golf carts.
Based on my understanding and previous research, roads that are too narrow for standard 4-wheel vehicles should be tagged as pathways (e.g., path, footway, cycleway), which aligns with the current wiki recommendations.
If it’s physically too narrow for a small car to fit through, I agree it’s mostly likely not a highway=service but rather a footway or cycleway.
I can see local exceptions in areas where motorbikes are the main way of getting around, although I can equally believe best tagging could be footway or path with motorcycle=yes or similar tagging. For example File:Alley in old city (7162772807).jpg - Wikimedia Commons is wide enough to fit a car so it could be service, File:Ngõ Phất Lộc.jpg - Wikimedia Commons is probably not wide enough for a car and personally I would use footway there (disclaimer: I am not a local mapper in Vietnam).
I think as long as a narrow street is not forbidden for motor vehicles and the smallest cars can pass it, it can be tagged as an alley. A maxwidth tag would be very useful
I suspect that this is down to naming again. In many languages and regions an “alley” or equivalent is a very narrow passageway (e.g. Polish alejka). My understanding is that is not its OSM meaning, though.
I recall a similar discussion previously happened about tagging of narrow ways in Venice, can anyone find the link?
According to the wiki, highway=path should be used if:
the main primary use of a way is unclear; or
the way has multiple intended primary uses and none is more significant than the others
So it should come down to figuring out whether a particular street is primarily for pedestrians, primarily for motorcycles, or primarily for both with equal weight.
Many of these streets were probably built for pedestrians and then allowed for motorcycles with lesser right of way, primarily to get to destinations. Local laws may clarify this.
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?
As cars are getting wider in Europe, this street may have been ok for most cars a few years ago. It is probably better not to treat it as a motorised way today, perhaps it would be better to map it as highway=pedestrian + motor_vehicle=yes + maxwidth=1.7 (+ bicycle=yes, probably). With motor_vehicle, maxwidth and bicycle, the precise value of highway only affects rendering. Describing the way in detail in borderline cases like this one is highly recommended.
I consider streets with a total width (including existing sidewalks/pedestrian lanes or space reserved for their construction) of less than 2 meters to be unsuitable and unintended for motor vehicles (cars, small vans). But note that maxwidth=1.7 is a legal restriction that may occur on streets wider than 2 meters, where the local authority has probably determined that the twists and turns along the road make it risky or impossible for wider vehicles to maneuver around buildings and obstacles.
In Thailand, narrow pathways are now primarily used by motorcycles, as walking has become less common. Unfortunately, there’s no specific designation like highway=motorcycleway for these paths, unlike the available types for cycleways, bridleways, and footways.
I agree that we should revert the conflicting change and improve it with something like the following:
Distinguish between 4-wheel vehicles rather than including all motor vehicles (which also cover narrower 2 and 3-wheel vehicles).
We could use a different photo for the section that indicates it’s illegal or combine it with the “Too Narrow” section, but I wanted to highlight the signage related to the illegal aspect.
As a non-native English speaker, it’s hard to follow the discussion.
Therefore, I will try to briefly write down the important points of discussion.
I don’t think it matters whether a four-wheeled vehicle can get around.
In some transportation cultures, small vehicles or motorcycles are the primary means of transportation.
I think there should be one classification.
In OSM, we classify roads (highway key) primarily by their use.
Therefore, I think it is better to categorize by use and treat other classification factors as sub-attributes.
In particular, ‘alley’, or ‘골목’ in Korean, is typically a very narrow street, but you don’t call it an ‘골목’ just because it’s narrow. Changing it now would cause even more confusion, but at the very least it’s a very confusing phrase, and I think it’s best to avoid using it.
I think the criterion for ‘highway=path’ should be whether it can be legally traveled by a motorized vehicle, not whether it can be traveled by a four-wheeled vehicle (i.e., width should not be the criterion, but only whether it can be traveled by people - or horses or bicycles).
Also, when it comes to car traffic, even the same 4-wheeled vehicle can be restricted by the width of the road, etc. I think this should be expressed as a sub-property.
In the UK, as far as I’m aware, the category of “street/alleyway too narrow for cars but legal for motorcycles” doesn’t really exist, so we don’t have that problem. (But I don’t own a motorcycle - most people don’t - so I wouldn’t know for sure.) The example in the picture would just be a footway I think.
Yes, @dieterdreist posted that picture as an example of something that would be tagged service=alley in Italy, with a description of “Quite narrow but legally accessible to motor vehicles”. Therefore it’s probably not a good idea to put it in the Wiki as an example of highway=footway.
@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?
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?
@adreamy : does this type of street exist in Korea? How are they tagged?
In Thailand, like in many other developing countries, there are countless narrow paths primarily used by motorcycles in urban, rural, and remote areas. These paths rarely have access restrictions.
They may serve as shortcuts in cities, provide access to homes, or even connect villages. In urban areas, they can resemble concrete footways, while in rural or remote areas, they look more like hiking trails.
We tag these paths as highway=path + motorcycle=yes, following past recommendations like this one, which is also used in neighboring countries.
If we accept that an alley only accessible by motorcycle can be tagged as service=alley, then by the same logic, every highway=path in thailand would need to be converted to highway=track, highway=residential, or highway=unclassified, depending on its usage.
This would cause renderers to display these narrow motorcycle paths as roads, and without manually adding motorcar=no, cars could be routed through them. For these reasons, I’m against making this change to the global wiki.
The main issue people (myself included) have with alley is that it requires highway=service, and those narrow old streets are not service roads, quote:
The highway=service tag denotes ways used for vehicle access to a building, service station, industrial estate, business park, beach, campsite, etc. It is also used for access to parking, driveways, and alleys.
I suspect the highway=service; service=alley combination comes from ambiguity of word alley, which means different things in different countries. Thus, the current service=alley Wiki page is tagged as “controversial” because of the “old medieval streets” section (I plan to edit it so as to clearly distinguish controversial and accepted usage).
However, that’s a bit of tangential issue. For the time being, I cautiously favor Fernando’s highway=pedestrian + motor_vehicle=yes + maxwidth=1.7 (although I’d prefer footway over pedestrian).
As ever, there are always edge cases. The note tags on some of those have very convoluted rules. See also here. Some of those may have motor_vehicle=no via a TRO, some may not, and several are sites of ongoing conflict between different types of users.
At a global level, we probably need highway=motorcycleway (motorised ways primarily intended for motorcycle traffic, but not cars) and highway=alley (narrow non-service public ways not intended for through traffic; different from service=alley). Anyone can start using them at any time, but app support would probably lag for many years (eg. what has been happening with highway=busway), in the meantime some mappers would undo those changes in order to get basic rendering and routing support, with some countries suffering more than others.
I agree we should mention 4-wheel vehicles (or perhaps “cars” for brevity as the smallest representative of the category). To keep it simple avoiding repetition, I would only mention that in the column headers of the table or maybe a table caption.
I wouldn’t add the new example from Italy yet, it probably needs more discussion. Not only it is a borderline case, there are many similarly narrow old streets in Italy and other European countries mapped as highway=pedestrian.
Based on my understanding and previous research, roads that are too narrow for standard 4-wheel vehicles should be tagged as pathways (e.g., path, footway, cycleway), which aligns with the current wiki recommendations.
like footway with motor_vehicle=yes? I don’t think this fits particularly well.
On the Italian telegram channel a few people were in favor of highway=residential with a maxwidth restriction, which somehow fits better, but makes it harder for renderers and routers to understand there should probably be specific handling, a distinct highway class is more straightforward (but harder to get started).
In retrospect I think it was maybe too lazy to subtag this kind of alley as subtype of “service”, maybe we should introduce highway=alley for streets (i.e. default to access=yes for all kind of traffic) that are extremely narrow.
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