[Tagging] Feature Proposal - RFC - cycle expressways

Pieter Vander Vennet pietervdvn at posteo.net
Fri Aug 5 10:30:46 UTC 2022 

Hi Jens,

As far as I know, a `motorway` is a road **with control of access**, 
i.e. this is a legal designation. If there is a traffic sign which 
forbids the use of non-car traffic, it should be mapped as motorway. 
This is very well defined and very clear to survey and thus clear to 
map. On the wiki, there is a table indicating which traffic signs are 
used for this worldwide: 
https://wiki.openstreetmap.org/wiki/Tag:highway%3Dmotorway.
This implies that simple asphalt road with e.g. only 1 lane in every 
direction but with the "only accessible to cars"-traffic signs /is/ a 
motorway - something I can see happening e.g. in the outback of Australia.

 > My standpoint is that cycleway=expressway shows a physical way of 
building a cycleway, in the same way that highway=motorway is a physical 
way of building a carriageway. This is principally independent from how 
such a road belongs to the road network, but of course the higher 
standards are used for the most important roads, so there is a high 
correlation in most areas.


The /way of building/ is mapped by having geometries of traffic 
interchanges (and motorway-link-tags), having maxspeed, surface tags, 
bridge tags, ...


 > The problem with "mapping the physical properties of the road" is: 
how would you map design speed, line of sight, curve radius, turning 
lanes, no level crossings, etc. in a way that an OSM data consumer (like 
a map renderer or a routing engine) could conclude "This is a high 
quality cycleway" and "This is a lower quality cycleway"?
If you tried to use the same argument on highway=motorway, how would you 
map it if you were to only "map the physical properties of the road"?

How are these things currently mapped? I'm breaking them down on how 
they can be handled:

- The maximum allowed legal speed is mapped with `maxspeed` and can be 
applied on cycleways too. In some legislations (e.g. belgium) a 
`highway=cycleway` implies a maxspeed of 30km/h; even though in some 
places  a lower maxspeed applies and is indicated with traffic signs.
- The `design speed` is mostly irrelevant for OSM. First of all, this is 
hard to survey in the field. Second, it is only a number that some 
engineers set up.
- line of sight and curve radius: can be calculated from the geometry of 
the road and/or based on other objects. Furthermore, this is hard to survey.
- no level crossings: again, can be calculated by iterating over the 
cycleway and checking if crossings exist
- Turning lanes are extensively discussed on the wiki and can be applied 
onto cycleways as well: https://wiki.openstreetmap.org/wiki/Key:lanes

Other stuff you mention on the wiki:
- "At least two lanes": use lane tagging
- Lanes wide enough: use `width`-tagging
- Limited access: use `foot=no`; `motor_vehicle=no` instead
- "no or very few at-grade crossings with other road classes (such as 
carriageways)": can be derived from the geometry. Furthermore, what is 
"very few"? Is this 2 crossing/km? 5crossings/km? 10 crossings between 
important destinations? What if the crossings are controlled?
- Gentler slopes: use `incline`
- Turning lanes: use turning lane tagging
- Right of way: there is tagging or that as well
- "Well lit": use "lit=*"

In other words, /all/ of the needed items can be tagged separately and 
step-by step in a non-ambiguous way. If you need to know which cycleways 
are up to a certain standard, you can do this with a geoquery. It is up 
to the data consumers to choose what makes something an `expressway` to 
them.

Another problem I do have with this proposal is that it is gonna be very 
hard to create an "express-way"-definition that is somewhat applicable 
worldwide and is easy to apply. For example, what in Belgium is 
considered a high-quality "cycle highway" is considered a normal 
cycleway in the Netherlands.
The definition in your email is "a cycleway that is built to a 
significantly higher standard than a regular cycleway."
What is a `regular cycleway`? How wide should it be? What surface should 
it have?
And what is a `significantly higher standard`?
What happens if - over the years - all regulary cycleways are upgraded 
to higher standards, but the original expressway isn't upgraded? Should 
all the regular cycleways get an expressway-tag as well? Or should the 
original expressway lose its tag then?
At what point does this happen?

And then I'm not even touching upon real-world difficulties. What if 
such an expressway is only half constructed? What if a non-level 
crossing will only be built in a few years? Road quality _will_ differ 
along the road in real-world cases. In Belgium, the cycle highways are 
sometimes mixed traffic, sometimes cyclestreets, sometimes high quality 
separate cycleways. Some municipalities give right of way to the 
cyclists, others to the cars crossing
Belgium is an excellent example, where `Fietssnelweg` precisely means 
the `route relation`, */not/* a certain standard of building as this is 
sometimes not possible.

The /intent/ of the people building it is irrelevant to OSM; only the 
physical result of their actions is.

 > "This is a high quality cycleway" and "This is a lower quality cycleway"

I'd like to point out two logical fallacies here. The first one is that 
there are many nuances in cycleway quality, it's not just a binary 
choice between "high" and "low" quality.

Furthermore, there is a huge difference in preferences of cyclists. Some 
will want to take the cycle highway to get to their job quickly, others 
will shun away from it and prefer the quieter, more scenic routes.
A desirable route for one cyclist might be horrible for another cyclist. 
With the company I work at, we went quite far in defining multiple 
aspects to a road (expected, speed, feeling of safety, feeling of 
comfort, ...) to mix and match this in different profiles. See 
https://github.com/pietervdvn/AspectedRouting/blob/master/BuildingAProfile.md 
for more info.

So, to sum it up: the definition is redudant and very hard to formalize, 
will encounter many edge cases. For someone like me, who has a ton of 
experience creating route planners and editing tools, such a tag is very 
hard to interpret.

(This being said: sorry for being so hard on you. Coming up with good 
tagging is extremely hard and time-consuming, so I hope I don't 
discourage you. I do appreciate the effort you are making though)


Kind regards,
Pieter

On 2022-08-04 17:14, Jens Glad Balchen wrote:
> Hi Pieter.
>
> It seems to me that there is some confusion as to what a "cycle 
> highway" and "cycle expressway" is. Perhaps if I try to explain what I 
> read, it will be more understandable.
>
> It seems you are arguing from a standpoint that a "cycle highway" is 
> primarily a road network classification -- i.e. "this road belongs to 
> a cycle network and this cycle network is our main network of 
> cycleways and we call it the cycle highway network", and of course 
> this road network classfication also carries some assumptions about 
> road quality, but are not linked 100%, so you will find varying 
> degrees of road quality on the cycle highway network.
>
> My standpoint is that cycleway=expressway shows a physical way of 
> building a cycleway, in the same way that highway=motorway is a 
> physical way of building a carriageway. This is principally 
> independent from how such a road belongs to the road network, but of 
> course the higher standards are used for the most important roads, so 
> there is a high correlation in most areas.
>
> Therefore, it seems to me that the two tags represent very different 
> information about a road and should be able to exist at the same time.
>
> So a cycleway can be tagged with a relation with your cycle_highway 
> tag to represent your cycle network information, and with my 
> cycleway=expressway to represent the road quality, and one tag does 
> not imply that the other tag exists.
>
> The problem with "mapping the physical properties of the road" is: how 
> would you map design speed, line of sight, curve radius, turning 
> lanes, no level crossings, etc. in a way that an OSM data consumer 
> (like a map renderer or a routing engine) could conclude "This is a 
> high quality cycleway" and "This is a lower quality cycleway"?
> If you tried to use the same argument on highway=motorway, how would 
> you map it if you were to only "map the physical properties of the road"?
>
> I'm very open to hearing your opinion on that, because I have also 
> thought that this could be a better principle; I just don't see how 
> it's possible.
>
> Jens
>
> On 04.08.2022 16:49, Pieter Vander Vennet wrote:
>>
>> Hi,
>>
>> We did extensive mapping in Belgium of the cycle expressways.
>> However, for the Belgian situation, introducing a new tag would *not* 
>> work and only complicate matters (especially because quite some parts 
>> are _not_ built up to code yet). Instead, mapping the physical 
>> properties of the road is better in combination with a relation, 
>> where the _relation_ indicates the cycle highway.
>>
>> See 
>> https://wiki.openstreetmap.org/wiki/Tag:cycle_network%3DBE-VLG:cycle_highway 
>> for more information and a worked out, in use tagging scheme.
>>
>> Kind regards,
>> Pietervdvn
>>
>> On 2022-08-03 23:52, Jens Glad Balchen wrote:
>>> Hi everyone.
>>>
>>> I propose a new value cycleway 
>>> <https://wiki.openstreetmap.org/wiki/Key:cycleway>=expressway 
>>> <https://wiki.openstreetmap.org/w/index.php?title=Tag:cycleway%3Dexpressway&action=edit&redlink=1> 
>>> meaning a cycleway that is built to a significantly higher standard 
>>> than a regular cycleway.
>>>
>>> Cycle expressways are becoming increasingly common across Europe. 
>>> They are distinctly higher quality cycling roads compared to regular 
>>> cycleways, equivalent to motorways for cars. highway 
>>> <https://wiki.openstreetmap.org/wiki/Key:highway>=cycleway 
>>> <https://wiki.openstreetmap.org/wiki/Tag:highway%3Dcycleway> 
>>> currently captures the basics of a cycleway, and adding lanes 
>>> <https://wiki.openstreetmap.org/wiki/Key:lanes>=*, foot 
>>> <https://wiki.openstreetmap.org/wiki/Key:foot>=no 
>>> <https://wiki.openstreetmap.org/wiki/Tag:foot%3Dno>, or width 
>>> <https://wiki.openstreetmap.org/wiki/Key:width>=* can provide 
>>> additional detail on the quality of the cycleway, but there are no 
>>> tags to capture the complete meaning of a road being a cycle 
>>> expressway.
>>>
>>> The definition is formalised in Norway as "sykkelekspressveg", in 
>>> the Netherlands and Belgium as "Fietssnelweg", in Sweden as 
>>> "supercykelväg", and in Denmark as "cykelsupersti". The term 
>>> "expressway" generally means the highest grade of highway and 
>>> captures all of these definitions and terms.
>>>
>>> See the details of the proposal here:
>>>
>>> https://wiki.openstreetmap.org/wiki/Proposed_features/cycle_expressways
>>>
>>> Please discuss this proposal on its Wiki Talk page.
>>>
>>> Cheers,
>>>
>>> Jens
>>>
>>> _______________________________________________
>>> Tagging mailing list
>>> Tagging at openstreetmap.org
>>> https://lists.openstreetmap.org/listinfo/tagging
>
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