No car, no sex - that's the rule for an experiment Zurich is launching to make prostitution safer for women and less of a public nuisance.
Teak-coloured open wooden garages, dubbed "sex boxes" by the Swiss media, are now open for business for drive-in customers in the Altstetten area of Switzerland's largest city.
The several dozen sex workers who are expected to make it their new hub will stand along a short road in a small, circular park for clients to negotiate with.
The park was built in a former industrial area nestled between a rail yard and the fence along a major highway.
The publicly-funded facilities - open all night and located away from the city centre - includes bathrooms, lockers, small cafe tables, a laundry and shower.
There are no video surveillance cameras, but the sex workers - who will need a permit and pay a small tax - will be provided with a panic button, and social workers trained to look after them will be available on-site.
Daniel Hartmann, a Zurich lawyer, said the move would mean more safety for the prostitutes, adding: "At least it's a certain kind of a shelter for them. They can do their business, and I respect them.
"They do a great job, and they have better working conditions ... They're not exposed to the bosses, to the pimps, in here."
On Saturday, several hundred residents, including many women and several journalists, flocked to the only "open house" that Zurich will offer to give the public a better idea of how their taxes are being used.
Most of the visitors said they came out of curiosity and have not really come to terms with the idea, but hoped it will at least improve safety.
Brigitta Hanselmann, a retired special needs school teacher from Embrach, Switzerland, said: "I have to think about it for a long time, because it's so incredible that a city offers that to the men, and it's interesting that there are many, many women here who are looking at it."
She called the sex boxes "an effort to control a thing that you can't really control."
Voters in Zurich approved spending up to 2.4 million Swiss francs (£1.6 million) on the project last year as a way of relocating the sex traffic away from a busy area where it had become a public nuisance, as well as addressing concerns over safety due to lack of sanitation, aggressive men and associated drugs and violence.
The city, which only allows prostitution in certain areas, also plans to spend 700,000 francs (£480,000) a year to keep the sex boxes running.
Along with improving safety for prostitutes, the sex boxes are seen as a way to curb illegal trafficking among crime syndicates. Prostitution, escorts and massage parlours are a thriving business in a nation with wealthy international clientele and tourists.
Zurich requires that street sex workers register with city and health authorities, and it offers health checks and requires that sex workers be at least 18 years old, in keeping with a Council of Europe convention on protecting children from exploitation and abuse.
In Switzerland, anyone who works in the sex trade must be at least 16, the legal age of sexual maturity. The income is taxed and subject to social insurance like any other economic activity. Prostitution has been legal in Switzerland since 1942.