If you live in New York City, you probably use a lot less gas (and produce a lot less pollution) than if you live in Minnesota. Why? Because everything's closer together in New York City. Stores and offices are closer to where people live, making it easier to walk to stores, restaurants and places of employment. Furthermore, there's a subway system that you can use when you aren't in the mood for walking. By designing communities so that everything is within walking distance and public transit is readily available, we can reduce the need for the personal transportation that produces such a large percentage of pollution. And wouldn't it be nicer to take a short walk to your office than a heavy drive through crowded lanes of traffic?