I work in Oslo (Norway) were we have to pay to enter/leave the city by car.

One of the issues with paid congestion fares, is that the cities tend to use it as tax – What you’ll need, is clear earmarking of the funds raised by the city, with the purpose of actually spending that income on improved conditions for driving.

Even without the earmarking, the city will still benefit from it’s income, so in that respect, for the city, it’s a win situation in all cases. I guess it’ll have to be up to the public to make sure that that income goes to improve the people that gave it away to begin with.