One approach that congested cities in Europe have taken to reduce downtown traffic is to specifically charge those contributing to the problem. While this may be reasonable to reduce some unnecessary traffic, what happens to the individuals who cannot afford not to drive to these areas? What if there isn't sufficient public transit to use as an alternative? (Here's a good article on the topic.)
I live in San Francisco and do not own a car. It's relatively easy here. I'd be in favor of congestion pricing. As a pedestrian, I'd hopefully spend less time dodging death by inattentive motorists on the main drag downtown (Market St). Our street cars and buses are significantly delayed in the throng of superfluous cars. The public transit system could be much more efficient without so much excess metal in its path...
But what about places like Los Angeles? New York? Chicago? What do the rest of you think about this?

