[Accessibility] seeking input on blog post for International day for persons with disabilities and OpenStreetMap

[Roland Olbricht]

Hello together,

We had and have a production ready wheelchair routing in the journey
planer of VRR, the traffic agency serving the 10 Mio. inhabitants Ruhr
region in western Germany,

The background of the project, see
https://pretalx.com/fossgis2019/talk/AP8QL3/
in German, is to offer door-to-door directions for walking and public
transit.

To get things done, we had narrowed the scope to mostly wheelchair
users. For these, the following tags turned out to be crucial but
usually missing on ways:

- width: While precision may help, the essential information is whether
the way is at least 1.25 meters wide.

- surface and smoothness: many quite common surfaces (e.g. uneven sett,
sand) are unusuable for wheelchair users. For some surfaces, the
smoothness tag is required because the surface itself may or may not be
wheelchair passable.

- incline: Turned out to be of less use than expected. Wheelchair users
wildly differ in their limits for incline, and the length does play a
role as well.

Would it make sense if I add these tags along with the stairs example on
https://hackmd.io/UrTjPdI7SKusc3neKkCmHA
or would you prefer a detached blog post on the project?

Best regards,

Roland