Specific to suburbs, there is criticism of modern suburban office developments, which are described as strings of disconnected wheelspoke-shaped nodes that are heavily reliant upon automotive transportation (Lang, 2003). This model impacts the urban environment in many ways, including its limited, predominant transportation mode (i.e., private vehicle). One of the typical missing benefits of these developments is a pedestrian facility around a central area of offices, shops, entertainment facilities, and homes. Suburbs are customarily more automobile dependent and adjacent to Interstate Highways. On the opposite spectrum, downtown business districts are scaled mainly to pedestrian traffic.
Land-use patterns and types of housing also impacted how cities in the United States developed. By separating residential, commercial, and civic activities, and by allowing the development of extremely low density suburban residential patterns, some areas of the United States exhibited a situation in which citizens must travel far to conduct basic activities (Jackson, 1987). Jackson furthermore elaborates on the crucial and ill-fated role that federally subsidized housing played in the development of United States’ current suburban landscape, especially in the Washington DC area.
For the District, “few mortgage guarantees were issued in the predominantly black central and southeastern sections of the district” (Jackson, 1987). The impact of this process is still resonating today and can be seen in the city’s demographic sectors. This also presently occurs in Atlanta; insurance companies profit from overcharging customers in minority neighborhoods and undercharging non-minority, suburban customers (Bullard et al., 2000). This encourages sprawl and its environmental consequences.
Undoubtedly, the world’s environment and people are impacted by road building and congestion. Road building has tremendous impacts on natural resources and communities across large geographic ranges. Many large cities are tasked with designing or altering their transportation networks to accommodate unchecked population growth. Of greater concern, global car registrations are growing more than double the rate of population growth; 50 million cars were registered in 1954, 350 million in 1989, and 500 million in 1997 (Schafer, 1997). This implies that private vehicle use is now becoming the unrivaled transportation mode choice across the globe.
As standards of living improve, especially in developing countries, more personal transportation is added to the roadways. This is demonstrated in Figure 3 (Sperling, 2002). Transportation mode and income level fluctuations vary greatly between cities, based in part on available infrastructure; however, populations with lower income generally take public transit, while higher-income populations take trips in personal vehicles (Sperling, 2002).
Figure 3. Transportation modes and increasing income (Sperling, 2002).
Due to this influx of vehicular traffic, some urban areas may rely upon road building as a fix, albeit a temporary one. Others may invest heavily in rail, pedestrian, or cyclist facilities. Local officials, public administrators, and engineers must collaborate to find a suitable assortment of sustainable transportation solutions.
Road building and congestion influence the environment in many ways, and both have local, regional, and global consequences. These effects generally center on natural resource consumption, environmental impacts, and social-economic impacts. For instance, making urban sustainability a goal in the transportation domain requires an evaluation of natural resource consumption. The impact on natural resources, renewable or nonrenewable, is a function of population, affluence, and technological resources (Ehrlich, 1968). Individuals have more control over limiting consumption than they do over population or technology.
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