[Routing] Snow chains required as temporary obstruction

[Patrick Strasser-Mikhail]

Hello!

I'd love to see good support for facultative (expectable, but not 
upfront known) obstructions in routing results.

Examples:
* Snow chains: Some roads have known requirements for snow chains in 
case of ice or snow. This is nothing that would strictly prevent taking 
a route via these roads, but it is of great use to know that upfront, 
and either prepare by packing your snow chains in the trunk, or asking 
your router to avoid roads with that hazard.

* The same applies to roads that are temporarily closed (night, winter), 
like pass roads. These could be tagged with e.g. access:conditional=no @ 
(Nov-Apr) or opening_hours=May-Oct like 
https://www.openstreetmap.org/way/26328760, 
hhttps://www.openstreetmap.org/way/53377253, 
https://www.openstreetmap.org/way/25555964

Currently, 
https://wiki.openstreetmap.org/wiki/Proposed_features/Snow_chains is 
under discussion.

I'd appreciate the view and comments from people concerned with routing. 
I'm sure there is still room for improvement or things to consider.

Cheers,
Patrick/trapicki
-- 
engineers motto: cheap, fast, good - choose any two Increase the
Awesome, reduce the WTF!