Source: adapted from R. Gilbert and A. Perl (2007) Transport Revolutions: Moving people and freight without oil, London: Earthscan / James & James.
Four main eras in transport revolutions can be considered for human history:
- Paleolithic. Outside hunting and seasonal migration trails, there was no particular transport technology of note. Where maritime distances were short, and coastlines were constantly visible, simple craft allowed people to cross narrow bodies of water. Long-distance movements involved on-foot migration across hemispheres and continents, mostly over several generations.
- Agrarian. The agricultural revolution enabled the gradual domestication of animals and plants, leading to the development of animal-powered transportation. The deployment of wheeled transport was also associated with the construction of road infrastructure, including bridges. This improved cohesion led to the formation of city-states, kingdoms, and empires that were best equipped to build such networks.
- Modern. This era began in the 15th century, with improvements in shipbuilding and navigation, enabling the crossing of vast oceans. Overland mobility remained largely constrained to trails, roads, and canals. Even more significant was the introduction of the steam engine and the subsequent developments of rail and steamship networks in the 19th century. Overland transport systems became faster than maritime transport for the first time.
- Contemporary. The early 20th century marks a surge in mobility with the setting of national railway and highway systems. However, it is the advent of air travel in the 1930s that enabled the most significant expansion of mobility, reaching a global scale in the second half of the 20th century. Telecommunication networks, initially telegraphic, telephones, television, and digital media allowed a substitution for mobility.