1. Even if I don't use `*:variable:values=`, `shoulder:variable=` and `lanes:variable=` are more accurate and consistent for "exceptionally in cases like accidents or breakdowns, on occasional traffic peaks (few days of year only, for example start or end of school holidays), road works or other traffic obstructions ahead. "
It seems static vs dynamic values isn't the reason of `*:variable=` , as discussions has mentioned the existence of boards that can only show one other speed. But they would still be considered `maxspeed:variable=` now. https://wiki.openstreetmap.org/wiki/Proposal_talk:Dynamic_maxspeed#Active_traffic_management_vs._LED_road_signs
For reference, the `*:condiitonal=` `wind_speed` restrictions always happen. 