Surveying the site, it looks like a general use drop-off lane with no special treatment for taxis. On the far side of the drop off area is parking access. There is a sign which says "bus/drive through lane weight limit" which may have been the source for the original drive-through tagging. Generic service road is probably still the best fit.

Attached photo(s):
https://westnordost.de/p/234710.jpg