Key:winter_service:priority

The winter_service:priority=* key is used in combination with the winter_service=* key to describe the priority level of winter service on the highway. Used values vary per area.

Values

Finland

Finnish Transport Agency classification

Classification details and a map of road classifications can be found on the agency's web site.

Priority class	Description
FI:Ise	Road usually clear. Salt is used.
FI:Is	Road usually clear. Salt is used.
FI:I	Road mostly clear. Salt is used.
FI:Ib	Road is serviced on a high level, but usually without salt.
FI:TIb	Urban road which is serviced on a high level, but usually without salt.
FI:II	Road is serviced on a level that allows safe traffic with care.
FI:III	Road is serviced on a level that allows safe traffic with care. Winter service after weather changes takes longer, and during that time the road may require special care to drive.

France

Some (all?) areas in France use a 4-rank classification according to their importance in the network, as with highway=*. Exclusively for winter service priority, not presuming about the means used:

Priority class	Description
FR:N1	Major route, it should be possible to use it without winter equipment such as snow chains (not accounting for special rules making them mandatory).
FR:N2	Standard route where most of the serviced routes are put into, quality depending on the available operator means.
FR:N3	Minor route, winter equipment are highly recommended as the service is lessened be it through salt and grit, or lower frequency.
no	No planned service. The users alone are responsible for their safety on those routes when winter weather occurs.

On top of that there's a classification about road's conditions. That's where each operator put the standard road condition for each aforementioned priority, and a lower limit under which additional methods could be used:

Priority class	Description
FR:C1	Clear roads.
FR:C2	Minor presence of snow or ice, users should navigate cautiously.
FR:C3	Presence of snow or ice, some important delay should be expected.
FR:C4	Road deemed unusable as is, use at your own risks.

United States

Washington

Seattle

Classification is based on Seattle Department of Transportation (SDOT) Winter Weather Storm Response Plan (WWSRP) Level of Service (LOS) designations.

The value of winter_service:priority=* on a given highway is equivalent to the value of the SI_LOS=* field for that highway in the Snow and Ice Routes dataset. Additional details can be found on the SDOT Winter Weather Response webpages.

Priority class	Description
1	"Gold" - all travel lanes clear of snow and ice
2	"Emerald" - one travel lane in each direction clear of snow and ice