text: Cars cause a great portion of polution to our environment. If citizens of countries around the world limit car usage, then the envirnment we live in will become more safe and less poluted. "Passenger cars are responsible for 12 percent of greenhouse gas emissions in Europe... and up to 50 percent in some car-intensive ares in the United States," (Rosenthal, 5). Since most cars use gasoline and diesel, they are emitting poisonous gases into the air, this could cause smog. By limiting car usage there will be a positive outcome on our envirnoment. "It will have beneficial implications for carbon emissions and the envirnoment, since transportation is the second largest source of America's emissions, just behind power plants," (Rosenthal, 34).