Travel Behavior, Economic Development and Urban Decentralization

Urban sprawl has become an issue of substantial interest to politicians and the general public.  There is concern that urban expansion is consuming a disproportionate amount of agriculturally and ecologically important land.

Principal Investigator(s):

Siim Sööt


Siim Sööt
Kazuya Kawamura
Joseph DiJohn
Duck-hye Yang
Lise Dirks
Paul Metaxatos
Piyushimita Thakuriah
Trisha Sternberg
Artan Alicolli
Erin Gravesravdes




To better understand the role of expressways in urban decentralization.  In the 1970s and 1980s the amount of urban land consumed vastly exceeded the growth in population.  The objective of this study is to determine what has caused this large growth in territory, how long one can expect it to continue and what steps might be taken to curtail the rapid increase in urban land consumption.


The redistribution and growth in population and employment are studied to examine when and why the changes took place.  While there is rather comprehensive information on population by small area since the beginning of the 1900s, comprehensive small-area employment data only date back to about 1970.  Additionally we examine travel behavior to understand how urban residents are adjusting to the increased traffic associated with the growing prosperity that is fueling urban decentralization.

Expected Results or Products:

Both the data examined and urban-growth theory suggest that prosperity is the greatest single contributor to population decentralization.  In the prosperous 1920s when the city of Chicago had its greatest decade of population growth most of the area within four miles of downtown Chicago lost population.  With the depression of the 1930s the decentralization slowed substantially but picked up again in the post World War II growth era in the 1950s.  In subsequent decades the core continued to decrease while fringe areas grew in population, but now the scale of the region is larger and in recent decades the population loss has extended into the inner ring of suburbs.   

The 2000 census, however, shows that the 100-year old phenomenon of declining populations in the core areas is changing.  Seven of the ten community areas closest to the Chicago CBD are growing and the inner-most northern suburbs that loss population in both the 1970s and 1980s exhibited substantial population gains in the 1990s.  While the growth in the far fringes of the metropolitan areas continues, there is now substantial infilling in core areas.  Expressways then have played a role in decentralization but prosperity, demographics and housing preferences seem to be more important.


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Siim Sööt
Urban Transportation Center
University of Illinois at Chicago
412 South Peoria Street, Suite 340
Chicago, IL 60607
Voice: (312) 996-4820
Fax: (312) 413-0006


Illinois Department of Transportation
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