Urban Environment and Sustainability
During the past two decades, the phrase “sustainability” has been a fundamental concept in architecture and urban planning. Notions like green design, smart growth; Traditional Neighborhood Development, etc. are among the recent urban planning flows that have environment-friendly design goals. However, the effects of urban form on environment have usually been neglected. This writing explains how urban built environment influences the urban environment and therefore the level of sustainability is affected. The main important parameter in this relationship is urban transportation. Urban form affects the transportation characteristics like travel behavior, Vehicle Miles Traveled (VMT), and automobile dependence. On the other hand, transportation characteristics influence the urban environment.
How Urban Form Affect Transportation?
Through the recent years, people have been drawn to live in compact and traditional neighborhoods. That has happened after the Neo-Traditional Development patterns like New Urbanism and Transit-Oriented Development (TOD) were introduced by some scholars as the alternatives to conventional suburban development. These urban design trends generally address dense, mixed-use, neighborhoods with high connectivity and accessibility. One of the goals of the urban planners in designing such neighborhoods is creating urban fabric that people can reach their destinations by foot. The houses are designed in a walking distance of the center of the neighborhoods and the amenities like pedestrian and bicycle routes are often included in the above-mentioned designs. The structure of such neighborhoods are connected and has a network-like figure, therefore the residents can have access to different parts of the neighborhood or urban fabric easily and safely.
The result is, according to some studies (for example see: Ewing, 2003), people walk more in such neighborhoods in comparison with auto-oriented ones. In a study, in 2003 Feng Liu showed that the capita vehicle travel in high-density developments is 27% less than the same factor in low-density suburbs.
The Effects of Transportation on Environment
Urban transportation is the greatest pollutant of the urban environment. Recently, the improvements of the automobile industry have led to optimization of the car engines. So the automobile emission of each car is now less than before. Nevertheless, due to the large number of the cars, the rate of pollution is still worrying. The automobile emissions are filling the environment with pollutants such as carbon dioxide, fine particles, and nitrogen oxides in the car-oriented cities of today. Normally the private car use in urban areas is associated with the pollutants, which are emitted. Therefore the number of urban travels that are made by personal automobiles are of importance.
This is the point that the importance of the structure of the urban form becomes clear. In Pedestrian-Friendly, Mixed-Use neighborhoods, like the traditional ones, people use less personal cars than in sprawling suburbs. So the environmental pollutions are less.
As is observable here, urban transportation is an important factor in the sustainability of the urban areas and the quality of the urban environment. On the other hand, we can see in similar studies like the one conducted by Liu, that how transportation is affected by urban form and land-use. Thus, the linkage between urban form, transportation, and environment is better defined.