text: In additon to increased safety, there would also be a significant reduction in the emissons of greenhouse gases. Greenhouse gases and smog have been polluting the atmosphere especially since the coming about of cars. It says in source four that transportation produces half of America's carbon emission. If car usage were to be limited or eliminated, there would be a noticable and significant decrease in the amount of carbon emissions in the air. Similarly, source one states that, " Passanger cars are responsible for 12 pecent of greenhouse gas emissions in Europe... and up to 50 percent in some car-intensive areas in the United States." If cars were to be ridden of, there would be much less green house gas poluting the atmosphere, therefore creating a cleaner environment and a brighter and longer future for the generations to come.