Categorisation of Key:smoothness values

[rhhs (Richard)]

@Supaplex030

it does fit the existing definition according to vehicle/tire types

Do you think this is true for the very_bad category?

@Supaplex030

This is because smoothness originated more from an off-road and car tradition and the concept had to be differentiated somehow for all roads and vehicles. For urban traffic, a car/motor vehicle is the worst possible “measuring vehicle”, because everything else on wheels in urban traffic (bicycles, scooters, wheelchairs, strollers, inline skates…) requires a finer differentiation in order for the smoothness concept to offer added value for evaluating road quality.

I agree that it’s worth striving for to make smoothness applicable for all roads and vehicles. However in practice this is impossible because the smoothness experience of different vehicles on the same highway is often inevitably different. The difference is biggest for 2-wheeled (single track) vs. 4-wheeled (double track) vehicles:

On this road, cars can hardly avoid the potholes, so for them I would tag this as smoothness=bad, while bicycles, motorbikes, etc. can easily slalom around them so for them I’d tag it as smoothness=good. On the other hand the pavement we discussed here How to map Key:smoothness - #2 by rhhs is quite smooth for cars (the broad tires would hardly notice the lengthwise gaps between the paving stones) while cyclists will have serious problems because a bicycle wheel can fit in those gaps and would make it dangerous to cycle on (similar to how tram rails are dangerous for cyclists).
Maybe we have to make a choice here, and decide that for smoothness below intermediate, the car is the primary “measuring vehicle” and if the smoothness is notably different for 2-wheeled vehicles, we should develop a new tag for it (bike:smoothness=* for instance, where bike = bicycle, motorcycle, etc.?)?

@Supaplex030

The result was indeed a partly “stricter” recommendation. The extensive discussions in the course of the smoothness implementation in StreetComplete then had a somewhat corrective effect, so that very_bad, for example, is now a clear exception category in the urban traffic of western cities.

Would you say that there is now full agreement between the wiki and the Gallery, and that any pictures in the Gallery that are in disagreement with the wiki should be moved/deleted/… ?

@Supaplex030

While you locate an “anchor point” somewhere between bad and very_bad, I would rather say that the category very_bad itself is an anchor point between “everyday categories” (excellent/good/intermediate/bad) and “off-road categories” (horrible/very_horrible/impassable).

By “anchor point” I meant that the category description is as clear as can be and undisputed. For me, very_bad clearly belongs to the “off-road categories” (with very rare exceptions in paved urban environments). I think the concept behind the smoothness classification system is that for every category, there is one or more vehicles for which the category is “usable” and the next worse category is “not usable” (with “usuable” being quite subjective). I think this is what you mean by “anchor point”.

@Supaplex030

For this reason, we also tried to define further evaluation criteria in the Berlin table, such as vibrations and influence on speed depending on the type of vehicle. Since we have seen in the past that pictures are sometimes not suitable for rating smoothness because they often do not show the actual driving characteristics, I think we should discuss more on such criteria and how to evaluate them.

That’s a good idea. I have a key bundle in the glove compartment of my car: if I hardly ever hear it → smoothness=excellent, if I hear it occasionally → smoothness=good, if I hear it all the time → smoothness=intermediate (or worse). Same with the lock chain around the saddle pin of my bicycle. StreetComplete is more visually oriented than I like, also because it’s hard to explain in text in such an app how to evaluate smoothness. Maybe we should develop a tutorial on smoothness that mappers have to pass first before they’re allow to map it

Looking forward to other opinions!