I guess its not the right approach to see this as a "has to break even" business. If on the bottom line all this has a positive effect on the entire city economy and quality of life, it will probably generate more money than what is collected from bus tickets and such.
Keep in mind that city centre which is over crowded with cars also costs a lot of money, in various ways. This is why they try to scare away car drivers from the central London area, by charging a stiff city road fee from those who want to drive into central London. Its 10 or 15 Pound or so per day! That gets many people to think about using the public transport, even if that costs also 5 Pound.
The cars - and also trucks - are becoming a serious problem nowadays. Also in Germany this is causing much trouble, and solutions for that are not easy to find. Not at last because our societies are designed to rely on the use of cars, to pamper the automobile industry. Changing that is not easy and will meet a lot of resistance.