I found this map quite interesting, just by highlighting various transportation mechanisms, you can tell where major cities are and where rural areas are. If you get rid of the carpool and driving alone, you can easily see where major public transportation is and these fall near cities, such as Chicago, Washington D.C. and New York. Areas with a high percent of people who walk, seem to be small towns and where people would maybe just work in their town, like Alaska or A small county in Colorado called San Juan, which happens to be the least populous county in Colorado.
