accounts for about one-third of the U.S. carbon emissions stemming from energy use. The reliance of the transportation sector on petroleum and its significant contribution to carbon emissions places mobility on geopolitical and climate change agendas.

ROLE OF THE GEOGRAPHICAL SCIENCES

Geographical patterns of human activity, such as settlement patterns or the locational arrangements of manufacturing or services, are shaped by patterns of mobility. With expertise in analyzing connections between spatial patterns and processes, the geographical sciences investigate the causes and consequences of mobility at varying spatial scales. Early work established that increases in accessibility provided through expansion of, and improvements to, the road network fundamentally altered the settlement system; as travel speeds increased, larger places grew, whereas smaller places declined and sometimes disappeared altogether (Garrison et al., 1959). Underscoring the relationship between mobility and land-use patterns, research has also demonstrated that improved access via expanded road capacity leads to increased traffic flows (Sheppard, 1995), which further reinforce differences between and among places. Moreover, some of those impacts are felt in places that are quite distant from the network segments that were improved (Giuliano, 1995). A remaining research challenge is to understand how to increase accessibility without exacerbating the traffic congestion that now plagues cities around the world.

Research has begun to identify the specific aspects of places that are salient to mobility processes and will therefore determine how increasing mobility will change the world differently in different places. Research to date suggests that the causes and consequences of increasing mobility will continue to have certain common threads across places, while also differing in important ways from place to place. However, much remains to be learned about the reasons for and outcomes of those differences.

The spatial separation of specialized land uses—such as food stores or city parks at the local scale or the manufacture of magnetic recording heads for 30 percent of the world’s computer hard drives in Dongguan, China (The Economist, 2008) at the global scale—makes economic specialization and scale economies visible on the landscape. Relatively inexpensive and dependable mobility from the local to the global scales has enabled this form of spatial organization to become truly global, with high levels of specialization twinned with long-distance linkages integrating the global space-economy (Dicken, 2003). Because connectivity varies from place to place (Figure 7.3), these mobility-based globalization processes have contributed to the patterns of inequality discussed in Chapter 8.

Place-specific policies can play a role in shaping the nature of the relationship between geographical pattern and process. At the intraurban scale, Giuliano (1995) showed that the land-use impacts of transportation investments are highly variable from place to place because they depend on local economic and political conditions. For example, the light-rail transit (LRT) built in Buffalo, New York, in the 1970s, failed to revitalize that city, whereas Portland, Oregon’s LRT has been central to a suite of policies that have supported the continued vibrancy of Portland’s city center and helped increase the share of travel made via public transit. Similarly, Mountz (2004) documented how international migration flows, specifically those involving human smuggling, are influenced by the micro decisions of immigration bureaucrats in destination places. Her ethnographic study of the differential receptiveness of places within Canada to immigrants illustrates the importance of governance practices and structures at national and provincial levels.

Geographical technologies, especially geographic information systems, facilitate the tasks of analyzing place-specific dimensions of mobility patterns and processes at varying spatial scales. At the regional level, the adoption of such technologies by planning agencies has transformed the ability of planners to create optimal designs and communicate projected impacts of different planning scenarios to the public (Nyerges, 2004). At the individual level, the rapid adoption of Global Positioning System (GPS) technologies is altering the mobility of vehicle drivers, pedestrians, and cyclists. Still largely missing are comparable systems for wayfinding indoors, as in large retail complexes, and for helping the visually impaired, such as “talking signs.” The potential impacts of the widespread adoption of these technologies are substantial. For example, if everyone is capable of finding a destination, then the destination need not advertise its location or adopt



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