An analysis of the relationship between urban form and the length of commute using centrographic measures

Several interurban and intraurban commuting studies have examined the relationship between urban form and the length of commute. This relationship has been analyzed in terms of agglomeration externalities, competition for land rents, spatial distributions of residences and employment, and households' location decisions and mobility status, among other factors. Understanding the relationship of urban form and the length of commute is important because it enables planners and policy makers to forecast changes in commuting patterns.;The present research analyzes the relationship between urban form and the lengths of commute based on the spatial distributions of residences and employment. Variables representing urban form were constructed using geographically weighted regression, penalized least square regression, and factor analysis with varimax rotation. These urban form variables include the degree of employment centralization, the degree of employment concentration, non-manufacturing employment growth, manufacturing employment growth, the degree of housing centralization, and the degree of housing concentration. The degree of centralization and concentration were defined separately to account for variations in urban forms.;Also, particular attention was paid to quantifying two measures of jobs-housing balance: one for within-zone commuting flows and another for across-zone commuting flows. This differentiation of the jobs-housing balance is important since the effects of jobs-housing balance are not necessarily confined within arbitrary administrative boundaries. The within-zone jobs-housing balance was measured in terms of density to describe how many residential workers are employed within their zone of residence. On the other hand, the across-zone jobs-housing balance was measured in terms of commuting space to describe how far these residential zones push residential workers to commute outward and pull non-residential workers to commute inward. This way, we can measure the effects of (de)centralizing and (de)concentrating residences and employment on commuting space for overall urban areas. Controlling for socioeconomic attributes of households in urban areas, the relationship between urban form and the length of commute was examined using path analysis.;The findings of the present research indicate that both centralized development and decentralized development have the potential--though of different magnitudes---to reduce the length of commute. Centralizing residences can reduce the length of commute more than de-concentrating employment. However, centralizing and concentrating both residences and employment is the most effective land use policy because it most significantly shrinks the commuting space of all commuters. Given the empirical evidence that households are more sensitive to residential attributes over commuting costs, further centralizing employment can increase the degree of spatial separation between workers and suitable jobs. On the other hand, de-concentrating jobs may not necessarily put those jobs within the grasp of qualified, nearby workers who desire them. The success of either kind of development depends on households' sensitivity to residential attributes and the availability of affordable housing. As expected, the differences between centripetal forces on firms and centrifugal forces on residences cause variations in the length of commute.