Segregated Land Use, VMT, and Greenhouse Gas Emissions
Trends characteristic of the post-war period, such the absence of coordination between local land use and federal transportation planning, various subsidies and economic incentives to suburban development, all accentuated the tendency toward what is now commonly called segregated land use. The idea behind early zoning, and one of the reasons modern suburban development takes up so much land, is that planners felt the need to separate land uses based on the compatibility of their functions: industrial, commercial, residential, and the like.
Though this was done for a variety of reasons, some of them still justifiable, it is increasingly clear that the extreme segregation of land uses leads to greater VMT, and by extension, higher levels of greenhouse gas emissions. Less intentional factors have produced similar effects: uncontrolled development, just as much a part of sprawl as the segregation of land uses, often follows transportation infrastructure designed to accommodate the automobile, thus locking high VMT into development itself.
While segregated land-use patterns generate more automobile trips, and, in turn, higher greenhouse gas emissions, they also impose greater financial burdens on area inhabitants. Transportation costs for those living in areas of decentralized urban development are consistently higher than for those living in denser, more mixed-use areas. Low transportation costs and low greenhouse gas emissions, therefore, go together, a correspondence that highlights the economic benefits of greater transportation efficiency.
To take Chicago for an example: in its study of the higher transportation costs of decentralized urban development, the Surface Transportation Policy Project (STPP) and the Center for Neighborhood Technology (CNT) gathered data on household travel patterns in Chicago area suburbs. The study found that households in those suburbs closer to Chicago, and therefore better served by transit, spend noticeably less on transportation annually than households in more distant, transit-poor communities.
| Lowest Average Auto Cost Chicagos Inner Suburbs |
$ |
| Oak Park | 5,232 |
| Evanston | 5,407 |
| Cicero | 5,444 |
| Berwyn | 5,501 |
| Harwood Heights | 5,573 |
| Elmwood Park | 5,618 |
| Highwood | 5,693 |
| Blue Island | 5,793 |
| Maywood | 5,740 |
| Forest Park | 5,727 |
| Highest Average Auto Costs Chicagos Outer Suburbs |
$ |
| Old Mill Creek | 7,068 |
| Mettawa | 7,049 |
| Bull Valley | 7,041 |
| Barrington Hills | 7,034 |
| Prairie Grove | 7,000 |
| Wayne | 6,987 |
| Wadsworth | 6,968 |
| Long Grove | 6,958 |
| Spring Grove | 6,955 |
| South Barrington | 6,947 |
Even when public spending on existing transit is factored into household transportation expenses, residents of more sprawling cities such as Houston, Atlanta, and Dallas-Ft. Worth still spend more on transportation than do residents of denser, more transit-oriented cities like Chicago, Honolulu, or New York -- on the order of $2,500 annually. Taken in the aggregate, such sums can reach large magnitudes.
While households make the daily choice of which travel mode to use, local and regional planners have the potential to reshape metropolitan regions in a way that could sustainably and systematically reduce the demand for automobile travel, and auto generated CO2 emissions. Travel demand studies indicate that strategies most likely to reduce automobile travel and ownership include compact development along transit lines, integrated land use zoning and development, frequent transit service, parking restrictions, well-maintained pedestrian and bicycle infrastructure and regional strategies to encourage infill instead of greenfield development.
As the examples above suggest, land use patterns that lower local CO2 emissions would have built-in energy efficiencies that would, over the long-run, save money from household transportation expenses, and the social costs of auto oriented infrastructure.
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Neighborhood Travel Emissions
Travel Emissions Across the
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