Got this on hand, motorway temporary carriageway crossovers which are closed by two-sided guardrails on retractable wheels when there’s no emergency or roadworks on the relevant section.
From above these crossovers look like this, the ways tagged as access=no… no need for routers to be misled. Usually when in use the maxspeed is 40kmh.
From the ground in TomTom quality
A tag for the barrier like removable=yes could not be found, a few entries exist for barrier=removable, but then where to put the guardrail.
Tag suggestions welcome, or another case of not mapping the function ie. JII (Just ignore it).

