Having sex in a car can be awkward if you get caught. To prevent this awkwardness, some European cities have created drive in "Sex Boxes."
They're basically parking spaces that have walls covering up the car so you can go along your business without disturbing the neighbors.
The idea seems to have originated in Germany, but Zurich has recently proposed building them there too, so that prostitutes can work in a more discrete way.
There are a lot of homes in Zurich that overlook the red light district. The police thinks they can't get rid of prostitution, but they can at least control it.