Several cities have already adopted a free transportation system.
Picture: logo of Aubagne's public transportation
Taking a bus or a tramway without paying a ticket or fearing to have a fine? This is the case in cities such as Aubagne in France who has adopted a free transportation system.
Article Innov'in the city on Aubagne public transportation (French): http://www.innovcity.fr/2010/07/26/la-gratuite-des-transports-a-aubagne-pourquoi-ca-marche/