prostitution

We have amenity=brothel but that's not a good fit imo. The wiki says it's for an "establishment." Nonetheless there are 16 occurrences worldwide of amenity=brothel + brothel:street_prostitution=yes, so it seems that's the most popular solution.

If it feels wrong (it's verging on "troll tagging"), you could just go with prostitution=yes, also in use. (Probably as a property of a bar or hotel, I'm guessing, so maybe the standalone version would just be amenity=prostitution -- but it seems that tag is not yet in use anywhere.)

Regardless, these tags would not go on the street itself, but rather on a node or area (or multipolygon) to the side.

J

edit - If you do map something like this, it's likely that another mapper might remove your addition as unverifiable. Consider adding a source tag with a link describing the regulations that permit this activity in this area, if possible. If the area is signed, describe the signs in your changeset comment.