In 2003, London instituted a $16 per day fee to drive within their "congestion zone". This reduced traffic and provided money to invest in their transport infrastructure. Now, Mayor Ken Livingston has proposed to charge owners of SUVs $50 a day to drive them within the congestion zone.
(Just a note about attribution. I first saw this story in today's Chicago Tribune. Since links to their web site require registration, I linked to the autoblog story for convenience.)
Imagine what a fee to drive within the Loop might do for Chicago? Yeah, like that'll ever happen.