This paper evaluates the influence of residential density on commuting behavior across U.S. cities while controlling for available opportunities, the technology of transportation infrastructure, and individual socioeconomic and demographic characteristics. The measures of metropolitan and local density are addressed separately. We suggest that metropolitan residential density serves principally as a surrogate for city size. We argue that markets react to high interaction costs found in large cities by raising density rather than density being a cause of those high costs. Local residential density measures relative location (accessibility) within the metropolitan region as well as indexing the level of congestion.
The purpose of this report is to summarize the findings and conclusions of TCRP Project H-1, Transit and Urban Form, with the large body of literature described in the literature review (TCRP Research Results Digest, No. 7, June 1995). In order not to duplicate the literature review, the researchers focus on a relatively small number of studies, most of them completed within the last 5 years, on the ways in which "urban form" and public transportation interact.
The purpose of the research is to provide guidance as to the land use characteristics in a corridor that can support new fixed-guideway transit services cost-effectively. It is postulated that land use characteristics in a corridor are a significant factor that drive the demand for transit service and, therefore, the value and effectiveness of such services. The research supports making the case for fixed-guideway transit where it is cost-effective and conversely lessening the demand for expensive fixed-guideway services where land use characteristics cannot support them. The research also makes it possible to suggest the nature of the changes in land use that could support transit.
TCRP Report 16 presents the results from Project H-1, An Evaluation of the Relationships Between Transit and Urban Form. The research team was under the direction of Parsons Brinckerhoff Quade & Douglas, Inc., and included Dr. Robert Cervero, Howard/Stein-Hudson Associates, Inc., and Jeffery Zupan. Six reports were produced by the research team; a decision was made by the project panel to publish four of the six reports as a two-volume set, in the regular TCRP series.
Findings from an empirical analysis to test the impacts of land-use mix, population density, and employment density on the use of the single-occupant vehicle (SOV), transit, and walking for both work trips and shopping trips are presented. The hypothetical relationships tested fo-cused on whether there is a relationship between urban form and modal choice, whether this relationship exists when controlling for non-urban form factors, whether this relationship is linear or nonlinear, and whether a stronger relationship exists between modal choice and urban form when they are measured at both trip ends as opposed to either the origin or the destination. A review of the literature and experiences sug-gested that a fair amount of information is known about the impacts of density on mode choice. However, considerable debate exists over whether density itself is actually the causal stimulus or a surrogate for other factors.