car.lua: winter_road/ice_road highway types and surface=ice/snow not reflected in routing cost

[aki1770-del]

Problem

car.lua has no entries for highway=winter_road, highway=ice_road, surface=ice, or surface=snow. OSRM routes over these ways at full speed as if they were normal paved roads.

OSM documents winter_road and ice_road as distinct highway values used in northern regions (Russia, Canada, Scandinavia) for seasonally passable routes — roads that exist only in winter when the ground or water is frozen. surface=ice and surface=snow appear on ice crossings and winter tracks.

Routing over these at full highway speed produces dangerously optimistic routes for drivers in winter conditions.

Current behavior

-- surface_speeds in car.lua — no ice or snow entry
-- speeds.highway in car.lua — no winter_road or ice_road entry

WayHandlers.surface() and WayHandlers.speed() already read these tables — the gap is purely missing entries, not missing logic.

Proposed fix

Add to surface_speeds in car.lua:

ice   = 20,
snow  = 30,

Add to speeds.highway in car.lua:

winter_road = 20,
ice_road    = 15,

Four Lua table entries. No logic changes. Speed values are conservative estimates consistent with safe winter driving — open to adjustment based on maintainer judgment.

References

• OSM wiki: Key:highway winter_road
• OSM wiki: Key:highway ice_road
• OSM wiki: Key:surface

AI-assisted — authored with Claude, reviewed by Komada.