查看更多>>摘要：Los Angeles, California, is generally considered the archetypal sprawling metropolis. Yet traditional measures equate sprawl with low population density, and Los Angeles is among the densest and thereby the least sprawling cities in the United States. How can this apparent paradox be explained? This paper argues that the answer lies in the fact that Los Angeles exhibits a comparatively even distribution of population throughout its urbanized area. As a result, the city suffers from many consequences of high population density, including extreme traffic congestion, poor air quality, and high housing prices, while offering its residents few benefits that typically accompany this density, including fast and effective public transit, vibrant street life, and tightly knit urban neighborhoods. The city's unique combination of high average population density with little differentiation in the distribution of population might best be characterized as dense sprawl, a condition that embodies the worst of urban and suburban worlds. This paper uses Gini coefficients to illustrate variation in population density and then considers a number of indicators—most relating either to the provision of transportation infrastructure or to travel behavior—that demonstrate the effects of low-variation population distribution on the quality of urban life in Los Angeles. This approach offers researchers, practitioners, and policy makers in Los Angeles and in smaller cities that are evolving in similar ways a useful and user-friendly tool for identifying, explaining, measuring, and addressing the most problematic aspects of sprawl.
查看更多>>摘要：A recently completed survey of office tenants in North Dallas, Texas, presented respondents with two hypothetical situations, each combining a temporary increase in commuting time with a temporary reduction in office rent. Respondents were asked whether the overall effect on their business would be positive, negative, or neutral. Although hypothetical, the questions were also topical. The respondents were all in the vicinity of a major highway project, the Dallas High Five Interchange, the construction of which has caused delays for some travelers. Econometric analysis of the survey responses provided estimates of the cost these office tenants attach to a temporary increase in the commuting time of their employees. This paper explains the derivation of these estimates and provides other findings relevant to their interpretation. The paper also motivates analysis by explaining how estimates of this sort can promote public awareness of the costs and benefits of highway projects.
查看更多>>摘要：Although the commonly accepted link between automobile ownership and automobile use has inspired some municipalities to experiment with neighborhood design in an attempt to influence both automobile ownership and travel behavior, the underlying relationship between neighborhood design and automobile ownership is still unclear. Evidence suggests that automobile ownership is tightly linked to income and household size and is less responsive to urban design. This research uses data from a matched pair of neighborhoods—one conventional and one neotraditional—to consider the relationship between neighborhood design and automobile ownership and the relationship between these factors and automobile use. Statistically significant differences were found for automobile ownership in the two neighborhoods. In addition, there were clear differences in automobile use—residents of neotraditional developments made fewer automobile trips, traveled fewer miles in their vehicles, and spent less time driving. This has implications for planning strategies that may help reduce automobile trips and miles separately from changes in automobile ownership.
查看更多>>摘要：Urban arterials are both promising and problematic locations for infill development and urban revitalization. San Pablo Avenue, a multilane urban arterial traversing nine cities and two counties along the eastern shore of San Francisco Bay in California, is considered here. The road developed over a long period: first as a streetcar line, then as an intercity automobile route, and most recently as a subregional traffic and transit route. Land uses from each of these transportation eras are still present along the avenue and range from neighborhood retail to automobile-oriented strip development. Recent transit service improvements and a strong housing market are leading to new developer interest in San Pablo Avenue. Findings are reported from interviews with 11 developers who recently built infill housing and mixed-use projects on or near the arterial. Developers see San Pablo Avenue's accessibility as a major asset but view transit services as a bonus instead of a necessity; transit availability allows developers to argue for reduced transportation impact fees and reduced parking requirements. Other aspects of the arterial's design, including high speeds and unattractive streetscapes, are problematic, as are zoning ordinances that require high parking ratios, large setbacks, and lengthy, discretionary approval processes. Small land parcels, incompatible adjacent uses, and high development costs are also drawbacks but, with creative development, are manageable. Local governments could provide incentives for private development along arterials such as San Pablo Avenue by improving street designs, reducing parking requirements, and updating zoning codes and approval processes.
查看更多>>摘要：This paper describes the empirical results of the estimation of discrete choice models for the location decision of moving firms in a spatial disaggregated environment. Systematic choice sets are applied to account for the choice context of each relocated firm. Each location alternative is described by a set of spatial attributes, including accessibility variables and the migration distance between the origin of the moving firm and the alternative. The firms analyzed are categorized by their mobility profile. These mobility profiles are homogeneous groups of firms with similar mobility characteristics. The models are estimated on an extensive revealed-preference data set with firm migration observations between 1988 and 1997 in the province of South Holland in the Netherlands. The results indicate that it is essential for modeling the spatial behavior of relocating firms to account for the original location. The accessibility of locations appears to be of modest importance in the location preference of firms; measures describing the distance to transport infrastructure appear to have the most significant influence. Finally, distinctive taste preferences are observed in firms with different mobility profiles and of different sizes.
Sarah E. KavageAnne Vernez MoudonJean E. MabryNicholas Pergakes...
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查看更多>>摘要：This work evaluates how local land use regulations and development patterns support transportation efficiency in urban and suburban areas. An efficient transportation system includes multiple transportation modes and reduces the need to drive alone. The research sheds light on how long-term efforts to devise transportation-efficient land development regulations have shaped new development. Data include surveys of zoning and development regulations in 19 study areas of Puget Sound, Washington, and reviews of 163 projects with a building permit. Analyses focus on the frequency of use of transportation-efficient elements in land use regulations, the frequency of adherence to these elements in projects, and the connections between area regulations and development. Fifty elements classified into six categories of transportation-efficient land use serve to evaluate the characteristics of regulations and permitted projects in each study area. The research shows that local jurisdictions have adopted many transportation-efficient regulations, and many of the projects reviewed follow these regulations. Compact development stands out as a major strategy used successfully in area regulations and permitted projects. Pedestrian-oriented environment and street-sidewalk connectivity are used at the project level but less so in regulations. Parking elements are weakest at the regulatory and project levels. Washington State growth management approaches to land use appear to become integrated into local regulatory frameworks and to be followed through in the implementation and development process. Work is needed regionally to increase the use of transportation-efficient land use strategies, with particular attention to parking regulations.
查看更多>>摘要：This study was motivated by the need for more empirical research on the urban form-travel connection. A two-tiered travel effect is expected from strengthening the urban form-travel connection: the enhancement of access to choices and a shift in travel mode choice from driving to nondriving. Existing studies have focused primarily on the second-tier effect but have largely omitted the first This study attempted to fill that gap. Through joint-logit modeling of choice set formation and travel mode choice in three cities—Boston, Massachusetts; Portland, Oregon; and Houston, Texas—the study measured the degree of automobile dependence in the three cities. It also estimated elasticities of automobile dependence and of driving probabilities with respect to land use densi-fication, transit access improvement, and control of motorization. There were large variations in the levels of automobile dependence and their elasticity estimates among the three cities. Public policies aimed at reducing automobile dependence should be formulated and evaluated based not just on the final outcome of modal split but also on the provision of travel options to travelers. As cities differ in their existing urban forms, currently available transportation services, and prevailing preferences of travel, it is important to recognize that the same set of policy strategies implemented in different cities is unlikely to generate the same level of effects in reducing automobile dependence.
查看更多>>摘要：There has been substantial discussion among planners about the influence of transport in residential location choices. The purpose of this paper is to analyze the importance of accessibility in explaining residential location choices. The paper addresses this issue by presenting and analyzing findings from the literature and results of a housing market estimation study in the Netherlands. The research findings for the Netherlands Illustrate that the transport system influences residential moves at three stages: in move-stay choice, estimation results show that households are less likely to move away from a more accessible location; travel tune variables are significant for all household types, and therefore changes in the transport system will affect the size of the housing market and search area of the households; the model estimation results suggest that accessibility of a specific location for many household types is not a significant variable in their location choice. Overall, the empirical results suggest that the role of accessibility is significant but small compared with the effect of demographic factors, neighborhood amenities, and dwelling attributes in explaining residential location choices. The empirical findings are confirmed by findings in the literature; the present results are located at the lower end of findings reported in the literature. An important factor contributing to this result is that accessibility changes among regions in the Netherlands are rather small.
查看更多>>摘要：There is growing interest in incorporating urban form indicators into transportation planning and travel analysis. These indicators typically are measured at a certain level of spatial aggregation (e.g., traffic analysis zone) and therefore are subject to the modifiable areal unit problem (MAUP) known primarily in the statistical and geographic literature but generally overlooked by transportation researchers. The presence of the MAUP can cause serious inconsistency in analytical results and consequently misinform policy making. This study diagnoses the MAUP in measuring urban form through empirical modeling of travel mode choice in the Boston, Massachusetts, region. Using data aggregated in grids with five cell sizes and at the transportation analysis zone, the census block group, and the block level, the study explores the sensitivity of coefficient estimates for population density, network pattern, and land use balance to data aggregation in predicting mode choice decisions. Having confirmed the presence of the MAUP, the study discusses three approaches for dealing with it. Using a grid with a cell size of 1/2 mi appears to be the most desirable method of data aggregation among the eight methods studied. The suggested improvements in methodology will help advance the inquiry on the link between urban form and travel.
查看更多>>摘要：Cities are constantly evolving, complex systems, and modeling them, both theoretically and empirically, is a complicated task. However, understanding the manner in which developed regions change over time and space can be important for transportation researchers and planners. In this paper, methodologies for modeling developed areas are presented, and spatial and temporal effects of the data are incorporated into the methodologies. The work emphasizes spatial relationships between various geographic, land use, and demographic variables that characterize fine zones across regions. It derives and combines land cover data for the Austin, Texas, region from a panel of satellite images and U.S. Census of Population data. Models for population, vehicle ownership, and developed, residential, and agricultural land cover are estimated; the effects of space and time on the models are shown to be statistically significant. Simulations of population and land cover for the year 2020 help to illustrate the strengths and limitations of the models.
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