I posted the same question a while ago in the german subforum. there seems not to be useful solution at the moment. we should make a proposal including a nice solution for tagging winter service, since there can be different values: no snow removal at all vs. full winter service vs. partial winter service (only on dangerous spots and so on). and iut is definitely an important information we should include in OSM. therefore we first need an overview of what types of winter service restrictions may apply in different countries in order to develop a generic approach. maybe there is even a need to include (namespace!) the type of winter service applied (road salt vs. snow plow vs. gravel, sand and so on)

might be a better approach instead of just using seasonal:winter=no which - in my opinion - is not an ideal solution.