[Tagging] uphill vs. incline=up - direction of travel

[Marc_marc]

Hello,

Le 18.12.22 à 20:19, Patrick Strasser-Mikhail a écrit :
> It was pointed out[3] that 'incline' is a tag and intended to indicate a 
> *direction* and amount of inclination of *the road in relation to the 
> mapping direction*, not the direction of the *vehicle driving* on the road.

that's not my reading/usage :
yes incline=* is about the direction of the way.
but it also not about the amount of inclination of the road,
it's about the maximum inclination of this segment :
you can have a route that goes up and then down to return to exactly
the same altitude. Depending on whether the maximum incline is up
or down, it will be incline=up or down and not incline=0/no.

Having never seen a road that requires chains to be put when
there is no ice nor snow, I wonder if the use of "@ (ice; snow)"
even makes sense, i find it useless.

To solve your problem, I think it is better to cut the highway=*
into sections that go only up or down not both.
(despite I find this sign absurd: a ice is just as slippery downhill
as it is uphill and I have never yet seen someone put their chains
at the top).

You can then simplify with
snow_chains=required
snow_chains:4wd:forward=no

PS: it seems that osm is using 4WD, not AWD,
see the badly named 4wd_only=*

Regards,
Marc