Designing Transit Systems

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In the United States, vehicles emit carbon dioxide (CO2) pollution in amounts second only to coal-burning power plants. The National Resources Defense Council (NRDC) has estimated that U.S. automobiles annually produce 1.5 billion tons (1.4 billion metric tons) of CO2, which combines with other greenhouse gases to contribute to the world’s current climate change.

New transit systems designed to support sustainability will be systems that reduce the waste of fossil fuels, decrease materials needed for building millions of miles of roads, and slow the buildup of atmospheric CO2. Transportation experts who plan these systems must also consider the current layout of U.S. cities. Some metropolitan areas are dispersed
cities; they grow outward and spread into formerly rural areas as their populations grow. Los Angeles, California, is an example of a dispersed city with a metropolitan area spreading more than 500 square miles (1,291 km2). Dispersed cities produce the familiar malady called urban sprawl, which leads to a greater dependence on cars. Compact cities by
contrast grow mostly in an upward direction and travel involves shorter trips on public transit.

The New York City borough of Manhattan is a compact city covering only 23 square miles (59 km2). It grows upward in skyscrapers rather than outward, making this island the most densely populated place in the United States. Compact cities conserve land and so benefit the overall environment, but countries like the United States, China, Canada, and Australia with large open land areas tend to develop dispersed cities compared with other parts of the world. It may therefore come as no surprise that these three countries rank 1, 2, 3, and 4, respectively, in carbon footprint, meaning their activities depend on fossil fuels and their wastes produce large amounts of greenhouse gases. Dispersed cities affect carbon
footprint in the following ways: (1) longer commutes burn excess fossil fuel; (2) excess fossil fuel combustion creates more greenhouse gases; (3) large numbers of commuters create traffic congestion, which wastes fuel and causes air pollution; and (4) a need for more roads and bridges, which use large amounts of building materials.

The important subject of transportation, including how certain characteristics of transportation damage the environment. The chapter explores new technologies that may change trends in transportation in industrialized nations. The main topics are the current state of transportation, personal vehicles, public transit, roads, and alternative vehicles. In addition, this chapter looks at the impact on the environment caused by rail systems, buses, trucking, airplanes,

This Los Angeles freeway has more traffic than it can handle, but Los Angeles is not alone
in confronting traffic congestion. Most metropolitan areas now rate traffic congestion
as one of their most serious problems. By developing advanced transit systems, cities
can remove some cars from the road and reduce exhaust emissions. The most difficult
obstacle to advanced transit systems is the American psyche, which has a strong
connection to its cars.

and cargo ships. All categories of the transportation industry face the daunting challenge of making vehicles that will be less destructive to the environment than current models.