section_path: Infrastructure/Transportation
section_name: Transportation
paragraph_text: Transportation
  
  Because cities rely on specialization and an economic system based on wage labor, their inhabitants must have the ability to regularly travel between home, work, commerce, and entertainment. City dwellers travel by foot or by wheel on roads and walkways, or use special rapid transit systems based on underground, overground, and elevated rail. Cities also rely on long-distance transportation (truck, rail, and airplane) for economic connections with other cities and rural areas.
  
  City streets historically were the domain of horses and their riders and pedestrians, who only sometimes had sidewalks and special walking areas reserved for them. In the West, bicycles or (velocipedes), efficient human-powered machines for short- and medium-distance travel, enjoyed a period of popularity at the beginning of the twentieth century before the rise of automobiles. Soon after, they gained a more lasting foothold in Asian and African cities under European influence. In Western cities, industrializing, expanding, and electrifying public transit systems, and especially streetcars enabled urban expansion as new residential neighborhoods sprung up along transit lines and workers rode to and from work downtown.
  
  Since the mid-20th century, cities have relied heavily on motor vehicle transportation, with major implications for their layout, environment, and aesthetics. (This transformation occurred most dramatically in the US—where corporate and governmental policies favored automobile transport systems—and to a lesser extent in Europe.) The rise of personal cars accompanied the expansion of urban economic areas into much larger metropolises, subsequently creating ubiquitous traffic issues with the accompanying construction of new highways, wider streets, and alternative walkways for pedestrians. However, severe traffic jams still occur regularly in cities around the world, as private car ownership and urbanization continue to increase, overwhelming existing urban street networks.
  
  The urban bus system, the world's most common form of public transport, uses a network of scheduled routes to move people through the city, alongside cars, on the roads. The economic function itself also became more decentralized as concentration became impractical and employers relocated to more car-friendly locations (including edge cities). Some cities have introduced bus rapid transit systems which include exclusive bus lanes and other methods for prioritizing bus traffic over private cars. Many big American cities still operate conventional public transit by rail, as exemplified by the ever-popular New York City Subway system. Rapid transit is widely used in Europe and has increased in Latin America and Asia.
  
  Walking and cycling ("non-motorized transport") enjoy increasing favor (more pedestrian zones and bike lanes) in American and Asian urban transportation planning, under the influence of such trends as the Healthy Cities movement, the drive for sustainable development, and the idea of a carfree city. Techniques such as road space rationing and road use charges have been introduced to limit urban car traffic.