To be a drunk driver you don't need to be drunk. In order to know when you've had one too much, McFarland presents you the Pissalyser: a black heat sensitive sticker placed inside urinals of bars and clubs across milan. The average time for a male to relief himself from one pint is 24.8 sec so if the person has had one pint too many and urinates for more than 30 sec, the pissalyser will show the message “It's taking you too long for having drunk only one beer. Call a cab.”
The operation was a huge buzz and the result was a 65% increase in consumers hailing cars from the places where the "pissalizer" has been put.