Cars Transform Cities, they kill them.
Or more directly "Cars Kills Cities" is well argued on the intriguing blog looking to improve transit solutions. To see how cars have taken over our cities, take a look at the following image of midtown Atlanta and the amount of space dedicated to temporary car storage. This is very similar to the concept of "dead space" I wrote about a long time ago, but nowhere as clearly illustrated.
As we acquire more, we necessarily use less since we only have 24 hours in a day, and cars are probably our most costly underutilized resource. (we are usually at home at least 8 hours, I think few spend 8 hours in their cars).