text: The big advantage about limiting cars is to help prevent the rapid spread of greenhouse gases the creates smog in cities. From source two you learn that cold nights and warm days cause the warmer layer of air to trap car emissions polluting cities even more. With these dangerous gases in the air, the world is in great danger of becoming unhealthy and we are to blame for this awful cause because of the over use of cars. By limiting the use of cars you limit the amount of pollution in the air.