The history of mass transportation is intimately connected to industrialization, urbanization, and the separation of residence from workplace. By the beginning of the 20th cent., London, New York, Boston, Paris, Budapest, and other major cities had fixed-rail subway systems (sometimes elevated); by the 1920s buses were common. In the United States, patronage of mass transit grew steadily from 1900 (six billion passengers per year) to 1927 (over 17 billion), but plummeted during the Great Depression. Patronage grew again during War II, peaking in 1946 at 23 billion riders, but then dropped steadily every year until the mild renaissance of public transit in the early 1970s.
The total number of riders in 1970 was less than that of 1910. The reasons for these declines are complex and often political. Los Angeles, for example, had over 1,000 miles of trolley and interurban lines before 1930; this system was taken over by a private company, dismantled, and replaced with noisy, polluting, and comparatively slow buses. Since few people chose to ride them, costs rose, thereby cutting the number of passengers further. To reduce costs, private companies eliminated outlying branches and smaller stations. These trends, along with inexpensive gasoline, suburban and highway development, the deterioration of older subway lines, and the greater freedom cars offered, helped turn the United States into a car culture.
However, as the public has grown increasingly concerned over the impact of cars on the environment and the quality of life in urban areas, there is growing support for the development of more efficient and comfortable mass transit systems. Models for such systems were developed in Europe and Japan. Trains in the Paris Metro, for example, operate on rubber tires and can reach speeds of 48 mph (77 km). Smaller cities are watching developments in Edmonton, Canada, which built a 4.5-mi (7.2-km) rapid transit system of lightweight trains at a cost of $65 million instead of adding five new freeways at ten times the cost.
In the United States, efforts to upgrade mass transit systems have experienced mixed results. The trend has been away from private ownership; by 1990 over 90% of North American mass transit was publicly owned and managed. The BART (Bay Area Rapid Transit) system serving San Francisco and neighboring cities maintained service during the 1989 earthquake, but it has never attracted the number of riders originally anticipated. Washington, D.C.'s Metro system (144 million riders in 1988) included a wider area of service and more efficient schedules. Currently buses account for 60% of mass transit rides in the United States; innovations such as articulated buses and reserved lanes on highways are balanced by the problems of noise, air pollution, and traffic. The issue of mass transit has come full circle; it is once again a central social and political issue.