text: The main cause of people wanting to limit driving is to protect the environment.  According to an article by Elizabeth Rosenthal, "passenger cars are responsible for 12% of greenhouse gasses in Europe... and up to 50% in some car intensive areas in the United States."  Emissions from car exhaust is polluting the air and creating smog in large cities.  According to Robert Duffer, Paris had to enforce a partial driving ban to clear the air of smog.  Some people want new suburbs to be built specifically to encourage the limiting of driving.  Limiting driving does lower the amout of smog and air pollution in cities.