Source: adapted from J.H. Ausubel, C. Marchetti, and P. Meyer (1998) �Toward green mobility: the evolution of transport�, European Review, Vol. 6, No. 2, pp. 137-156.

Growth of the US Transport System, 19th - 21st Century

The growth of transport systems, as the case of the United States exemplifies, went through a series of waves of growth, maturity and decline as massive investments in infrastructures and development of the system were taking place. Each time there is a substitution from one mode to the other, moving to higher level of speed (and sometimes efficiency). A paradigm shift represents an event that mark the prominence of transport system, often characterized by the completion of a significant infrastructure project which starts to impact economic and spatial systems. A peak year is when the system is about to reach maturity and experience a slow down in its growth.

The development of the canal system lasted 30 years (ΔT, time for the transport system to grow from 10% to 90% of its full extent) and peaked around 1836. Its paradigm shift took place in 1825 with the opening of the Erie Canal and its maturity and decline was caused by the emergence of a more flexible and efficient inland transport system; rail. The growth of rail in the later part of the 19th century took off with the completion of the transcontinental railway in 1869 marking its paradigm shift. By the late 19th and early 20th century most of the American territory was serviced by rail. Road transportation emerged in the beginning of the 20th century, especially after the introduction of the Model T in 1913. The growth of the road transport system marked the maturity and downfall of rail transport, especially for short and medium distances. Surprisingly, the development of the Interstate Highway System marked the maturity of the road transport system as the national trade was increasingly taking place along major high capacity road corridors between major metropolitan areas, lessening the need for regional road construction. The latest wave of development is related to air transportation, that peaked around 2001 and is expected to last about 70 years. A key event that marked the dominance of air transport was the introduction of the Boeing 747 in 1969 which opened air travel to the masses. The next transport technology is likely to be Maglev (Magnetic Levitation), but little is known about its potential impacts and which event would trigger a paradigm shift.