The per-capita car ownership ratio in China will increase by 67% to 40 cars for every 1,000 citizens by 2010 from the current 24, according to a report by Chinanews. By contrast, the US has 765 vehicles per 1,000 (2002 data), while Europe (including the FSU countries) has an average of about 300 vehicles per 1,000. (UNECE).I wonder what the numbers are when you exclude the FSU countries. This PDF does show that Germany - probably the closest to the US in terms of wealth - has fewer cars than the US, per 1000 people. In fact, I'd wager this understates the case - the German lower class is much better off than the American lower class, but car ownership doesn't seem to increase.
My theory is that German cities are more accessible by foot, bike, and mass transit, but I've never been so who knows.