text: Passenger cars cause 12% of greenhouse gass admitions in europe, and up to 50% in some car-intensive areas in the Unites States. If we got rid of most privetly owned cars though, it world bring that pecentige down tramendously. In Paris the record high pollution finally had them pass a partial driving ban untill the thick smog cleard the city streets. congestion was down 60% in the streets of paris, and after 5 days of intensifying smog it had finally cleard.