There is an interesting article in The Guardian Online today, about the public transport network in Vienna which is widely considered to be one of the best of the world.
Since 2013 local residents have been able to take advantage of an annual ticket that costs just €365 - the equivalent of just 1 euro a day. This compares with €8 currently for a one-day ticket. This has been a real boon for people on lower incomes, and even the better-off have been buying them, to have and use "just in case". It is reckoned that 1.1 million of the City's 1.9 million population have a long-term pass (there are even cheaper passes for children and students).
Naturally the system is generously subsidised, at around €700million a year.
Hermann Knoflacher, a professor and urban planning expert who has worked on the city’s transport infrastructure since 1963, reckons the key to Vienna's success is not just the impressive level of service and the low fares, but also gradual restrictions on car use. He says:
“Cars are like water, they fill any space you give them,” he said. “It’s great that the Germans  want to introduce the cheap subway fares, but it’s only part of the solution. If you don’t really go after the cars, it will never work.”