ZURICH » No car, no sex.

That’s the rule for an experiment Zurich is launching today to make prostitution less of a public nuisance and safer for women.

Switzerland has long been famous for its mountaineering, chocolate and precision watches, but a lesser known aspect is its legal prostitution since 1942, for which its largest city is one of the main centers in Europe.

Fashionably teak-colored open wooden garages, popularly called "sex boxes" by the Swiss media, will be open for business for drive-in customers. 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 choose from and 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 center — include bathrooms, lockers, small cafe tables and a laundry and shower. Men won’t have to worry about 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 on-site social workers trained to look after them.

As far as Daniel Hartmann, a Zurich lawyer, is concerned, it’s a win-win situation.

"Safety for the prostitutes. At least it’s a certain kind of a shelter for them. They can do their business, and I respect them," he said. "They do a great job, and they have better working conditions here. … They’re not exposed to the bosses, to the pimps, in here."

On Saturday, Hartmann was one of several hundred residents, including many women and a small throng of journalists, who flocked to the only "open house" that Zurich will offer to give the public a better idea of how its taxpayer money has been used.

Most of the visitors said they came out of curiosity and haven’t really come to terms with the idea, but hope it will at least improve safety. Others were amazed and a bit amused that a whole group of strangers would spend a rainy afternoon openly discussing professional sex.

Brigitta Hanselmann, a retired special needs schoolteacher 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 ($2.6 million) on the project last year as a way of relocating the sex traffic away from a busy downtown area where it had become a public nuisance and safety concern 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 ($760,000) a year to keep the sex boxes running.

Jean-Marc Hensch, a business executive who heads a neighborhood association in another part of Zurich, said he hopes the sex boxes succeed because otherwise the prostitutes might return to his area. He also cited the disgusting lack of sanitation in other city areas where prostitutes and their clients defecate and urinate in the streets and gardens, or have sex in the open because they have nowhere else to go.

"It’s an experiment," he said. "It was absolutely urgent to find a solution."

The drive-in garages, or sheds, have no doors to shut and come equipped with an emergency call button on the passenger side of the structure that sets off a flashing light and a loud alarm inside an adjacent office building where the city will post social workers specially trained to provide a measure of security. The Zurich police say they will beef up patrols around the perimeter to protect the sex workers when they leave and enter.

Modeled after the drive-in brothels used in several cities in Germany and the Netherlands, which have had mixed success improving safety, the sex boxes will be open daily from 7 p.m. to 5 a.m. The city painted the outdoor bathrooms in soft pink and blue, strung colorful light bulbs among the trees and posted creative signs encouraging the use of condoms to spruce the place up a little and make it seem more pleasant.

"We built the place to be secure for the sex workers. It also had to be discreet for the sex workers and the clientele," said Michael Herzig of Zurich’s social welfare department. "But we thought if we build the place, we can also make it look good."

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 parlors are a thriving business in a nation with wealthy and 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.

But some cities have their own rules and some of the 26 Swiss cantons (states) have adopted separate legislation on prostitution. A special unit of the cantonal police force, usually the vice squad, carries out inspections of prostitutes in red light areas.

No video surveillance was installed at the sex boxes, so as not to scare off business, but also because police and city officials concluded after studying the handful of other such facilities in Europe that the only thing that would improve safety is an on-site security presence. To use the place, sex workers also must obtain a special permit, at a cost of 40 Swiss francs ($43) a year, and pay 5 francs ($5.40) a night in taxes, which helps the city offset maintenance costs.

"We can’t solve the whole problem of exploitation and human trafficking," said Herzig, "but at least we want to reduce the harm, especially the violence."