[OSM-dev] smoothness data in gpx files for GPS tracks on osm.org?

[Johannes]

Hello,

I wanted to get some opinions about an idea of mine.

I consider data on the smoothness/roughness of routes to be quite important for cycle routing in order to plan optimal routes. Up to now, this has not played a major role in bicycle routes, as far as I know. Therefore, I would like to make a small improvement of the surface data for paths in Openstreetmap.

You can see on mapillary photos what kind of road surface there is on a cycle path, but you can't deduce reliable data about the smoothness of it.

A first technical idea was to record a track as a GPX file enriched with a vibration coefficient (IRI, International Roughness Index, dont know the exactly format yet) recorded by a smartphone while riding a bike. 
The GPX file format seems to be flexible enough (extension?) to store additional data such as this coefficient.

Therefore a central data repository is needed.
Do you think it's a good idea to store such enriched GPX data in the public GPS tracks repository on openstreetmap.org and make appropriate changes to the database schema and API so that these additional metadata are preserved when exporting GPX, so that on the one hand the GPS tracks can be made available to the public and on the other hand special client  software can visualize the vibration metadata.

What do you think? 
Greetings Johannes