( CNN ) -- In an attempt to reduce open street prostitution and to improve security for sex workers , Switzerland 's largest city , Zurich , is opening `` sex drive-ins '' Monday . The nine garage-style structures , located in Sihlquai , a former industrial zone in the city , are equipped with alarm buttons and guarded by security personnel to ensure the safety of the prostitutes . Customers are not allowed to leave the area with the sex workers . Read more : Brazil drops 'happy being a prostitute ' ad campaign . `` Prostitution has escalated in the city , '' said Michael Herzig , from the Zurich social services department . `` It was done out in the open on the street and men harassed passers-by . `` It was noisy and dirty because men took the prostitutes to a side street and left used condoms on the streets . The drive-ins are more discreet and safer . '' Herzig leads the project , which has cost 2.4 million Swiss francs ( $ 2.6 million ) to set up . `` The project is extremely controversial . Prostitution is about morals and religion . But we leave these things aside and see it as a business . The humanitarian aspect is more important for us , '' said Herzig . Around 30 to 40 women are expected to work at the site each night . Sex workers have to pay 5 Swiss francs per night to make use of the so-called `` sex boxes , '' but customers do n't have to pay an entrance fee . Read more : Ahead of Brazil World Cup , free English classes planned for prostitutes . The drive-ins are open daily from 7 p.m. to 5 a.m. and can only be accessed by car . Drivers have to follow a clearly marked route to get to the area , where customers and sex workers can discuss the services offered and agree on a price . The client can then drive into the allocated box , where the service is provided . There are also showers , toilets , a kitchen and washing machines for the women to use , as well as an advice center where they can seek help from social workers . A gynecologist comes in once a week to offer health checkups for the women . The city 's social services department is running the whole operation and also offers crash courses in German and self-defense courses for the women on site . `` All of this will enhance the sex workers ' living and working conditions , '' Herzig said . Prostitution and consumption of paid sex are legal in Switzerland . Prostitutes are considered self-employed and are liable for taxation . `` We are trying to promote the independence and self-determination of the sex workers , '' he said . `` It 's not a unique concept . We went to Utrecht in the Netherlands and Cologne and Essen in Germany , where similar projects exist , to speak to organizers . In Utrecht it 's been successfully implemented since 1986 . '' As well as backing from the authorities , the project in Zurich has a democratic mandate : A referendum was held in March 2012 , with 52 % of voters in favor .
Sex workers will operate from garage-style structures with alarm buttons and guards . The move is intended to take prostitution off the streets of Zurich , says project leader . Score: 6 The women can get health checkups on site , as well as advice from social workers .