Yesterday 14th Ward Alderman Edward Burke proposed that the city investigate a tax for all drivers into downtown Chicago, similar to London's tax (apparently NYC is also considering it).
I'll assume that the reason he's suggesting it is to: raise some money for the CTA (this would be a good thing), get people to consider other means of coming into the city, other than the single car driver coming in from the far reaches of the city and burbs (this too would be a good thing), and perhaps slow air pollution (also a good thing).
This idea is just never going to fly. If we already had a better public transport system -- a system in which it would actually be feasible for most people to come into the city by bus or train -- then maybe putting a tax on those who don't use it would be good and fair.
How about we give tax breaks to those of us who choose to walk, ride a bike, or take a bus into the city already? I'm a much bigger fan of that. But then, I believe an idea like that would never cross the mind of a city official, since about 99% of them drive a car to get anywhere.