Few years ago I was in Norway for a wedding. At a lunch, few days before the wedding, I offered to give a lift to a few people that were staying at the same hotel.
I ordered a light beer. Within a few seconds, I was notified that nobody would drive back with me. They have an Absolute Zero tolerance policy. If you sniff a beer, you’re driving alone and nobody will take a ride with you. The reason: If caught in a car when the driver is over 0.5 g/l , the driving license of everybody is suspended. Everybody meaning all passengers. As a passenger, if you have a driving license, you know that you should not let someone drive drunk. It’s really extreme, but it works very well.
--Steve, Freakonomics, on group enforcement through group punishment