Browsing by Subject "Vehicle miles traveled (VMT)"

Now showing 1 - 7 of 7
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    Community design and how much we drive
    (Journal of Transport and Land Use, 2012) Marshall, Wesley; Garrick, Norman
    The preponderance of evidence suggests that denser and more connected communities with a higher degree of mixed land uses results in fewer vehicle kilometers traveled (VKT). However, there is less agreement as the size of the effect. Also, there is no clear understanding as to the aspects of community design that are most important in contributing to lower VKT. One reason why there is some confusion on this point is that past studies have not always made a clear distinction between different community and street network design characteristics such as density, connectivity, and configuration. In this research, care was taken to fully characterize the different features of the street network including a street pattern classification system that works at the neighborhood level but also focuses on the citywide street network as a separate entity. We employ a spatial kriging analysis of NHTS data in combination with a generalized linear regression model in order to examine the extent to which community design and land use influence VKT in 24 California cities of populations from 30,000 to just over 100,000. Our results suggest that people living in denser street network designs tended to drive less. Connectivity, however, played an adverse role in performance.
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    Examining interaction effects among land-use policies to reduce household vehicle travel: An exploratory analysis
    (Journal of Transport and Land Use, 2019) Choi, Kwangyul; Paterson, Robert
    Numerous studies have suggested that land-use policies can reduce vehicle travel through mode shifting and reduced trip lengths and generation of fewer or more efficient trips. The findings from previous studies also suggest that the combined effect of two or more land-use policies can be significant, although the effects of individual policies appear to be modest. These studies present area-wide impacts of land-use policies on travel and suggest that their effects are additive. However, very little is known about how each land-use policy interacts with the others at different levels of development intensity to reduce vehicle travel. In this study, we explore how three well-known land-use strategies (densification, mixed-use development, and street network improvement) interact with each other by testing possible combinations of land-use factors and focus on how these interactive effects vary by the level of development intensity. Employing ordinary least squares regression analysis using a dataset created for the Austin metropolitan statistical area (MSA) (using 2006 Austin Travel Survey data), we examine the impact of land use on household vehicle travel. Our findings suggest that interaction effects occur, but they vary by development intensity. The results of this study show the importance of considering both threshold (development intensity) and interaction (combination of policies) effects in understanding how land-use factors do and do not affect travel (based on their interactive opposed to only their direct and additive effects). Though this paper uses data from just one MSA and thus is merely suggestive, it does point to a possibly more nuanced use of the commonly prescribed planning and design policy variable to account for variation in effectiveness based on differences in development intensity. For example, we find that greater land-use intensification has higher efficacy in changing vehicle travel behavior in areas with relatively higher development intensity. Future research should include data from a broader array of metropolitan areas and incorporate additional predictor variables that were unavailable for this analysis.
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    How built environment affects travel behavior: A comparative analysis of the connections between land use and vehicle miles traveled in US cities
    (Journal of Transport and Land Use, 2012) Zhang, Lei; Hong, Jinhyun; Nasri, Arefeh; Shen, Qing
    Mixed findings have been reported in previous research regarding the impact of built environment on travel behavior—i.e., statistically and practically significant effects found in a number of empirical studies and insignificant correlations shown in many other studies. It is not clear why the estimated impact is stronger or weaker in certain urban areas and how effective a proposed land use change/policy will be in changing certain travel behavior. This knowledge gap has made it difficult for decision makers to evaluate land use plans and policies according to their impact on vehicle miles traveled (VMT), and consequently, their impact on congestion mitigation, energy conservation, and pollution and greenhouse gas emission reduction. This research has several objectives: (1) re-examine the effects of built-environment factors on travel behavior, in particular, VMT in five US metropolitan areas grouped into four case study areas; (2) develop consistent models in all case study areas with the same model specification and data sets to enable direct comparisons; (3) identify factors such as existing land use characteristics and land use policy decision-making processes that may explain the different impacts of built environment on VMT in different urban areas; and (4) provide a prototype tool for government agencies and decision makers to estimate the impact of proposed land use changes on VMT. The four case study areas include Seattle, WA; Richmond-Petersburg and Norfolk-Virginia Beach, VA; Baltimore, MD; and Washington, DC. Our empirical analysis employs Bayesian multilevel modeling method with various person-level socioeconomic and demographic variables, and five built-environment factors including residential density, employment density, entropy (measuring level of mixed-use development), average block size (measuring transit/walking friendliness), and distance to city center (measuring decentralization and level of infill development). Our findings show that promoting compact, mixed-use, small-block, and infill developments can be effective in reducing VMT per person in all four case study areas. However, the effectiveness of land use plans and policies encouraging these types of land development is different both across case study areas and within the same case study area. We have identified several factors that potentially influence the connection between built environment shifts and VMT changes including urban area size, existing built environment characteristics, transit service cover- age and quality, and land use decision-making processes.
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    The impact of residential growth patterns on vehicle travel and pollutant emissions
    (Journal of Transport and Land Use, 2011) Niemeier, Deb; Bai, Song; Handy, Susan
    In light of the increasing reliance on compact growth as a fundamental strategy for reducing vehicle emissions, it is important to better understand how land use-transportation interactions influence the production of mobile source emissions. To date, research findings have produced mixed conclusions as to whether compact development as a strategy for accommodating urban growth significantly reduces vehicle travel and, by extension, mitigates environmental impacts, particularly in the area of air quality. Using an integrated simulation approach coupled with long-term land development scenarios, we conducted an assessment of the impacts of different long-term primarily residential growth patterns on vehicle travel and pollutant emissions in the eight counties of the San Joaquin Valley region in central California. The results suggest that higher residential densities result in slightly decreased regional vehicle travel and emissions. Our comparative analysis also suggests that the effects of future land use growth patterns may vary among different spatial areas. That is, compact growth strategies can result in significantly more travel and emissions changes in already fairly urbanized counties. This work indicates a minimum density threshold of approximately 1500 households per square mile is necessary to achieve commensurate emissions reductions relative to existing densities.
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    Measuring the impacts of local land-use policies on vehicle miles of travel: The case of the first big-box store in Davis, California
    (Journal of Transport and Land Use, 2013) Lovejoy, Kristin; Sciara, Gian-Claudia; Salon, Deborah; Handy, Susan; Mokhtarian, Patricia
    Concerns over climate change have brought new impetus to the goal of reducing vehicle travel through land-use policy. To determine the degree to which land-use policies are effective in reducing vehicle travel, studies are needed that measure and compare vehicle travel both before and after a land-use policy change. The opening of the first big-box retail store in Davis, California, represented a major change in the retail landscape and an unusual opportunity to study its effect on shopping travel. Surveys of residents' shopping behavior conducted before and after the opening of the store revealed a significant shift in where people shopped and a measurable reduction in overall vehicle miles traveled (VMT) for shopping. Although the observed change in VMT is specific to the Davis context, the findings support the general proposition that bringing retail destinations closer to residences could help reduce vehicle travel, particularly where the comparable alternatives for the newly introduced store are far away. The study also offers important insights into the challenges of conducting before-and-after studies of the impact of local land-use changes.
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    Transportation impacts of affordable housing: Informing development review with travel behavior analysis
    (Journal of Transport and Land Use, 2018) Howell, Amanda; Currans, Kristina M.; Gehrke, Steven; Norton, Gregory; Clifton, Kelly J.
    Planning for affordable housing is challenged by development policies that assess transportation impacts based on methodologies that often do not distinguish between the travel patterns of residents of market-rate housing and those living in affordable units. Given the public goals of providing affordable housing in areas with good accessibility and transportation options, there is a need to reduce unnecessary costs imposed by the potential overestimation of automobile travel and its associated impacts. Thus, the primary objective of this paper is to examine and quantify the influences of urban characteristics, residential housing type, and income on metrics commonly used to assess the transportation impacts of new development, namely total home-based trips and home-based vehicle trips. Using the 2010-2012 California Household Travel Survey, we regressed these metrics on urban place type, regionally adjusted income, and housing type, controlling for household size, weekday travel, and home location. The results indicate significant reductions in vehicle trip making with lower incomes and increasing urbanization. These findings support more differentiation of affordable and market-rate housing in the development review process and emphasize the need for development standards to be more sensitive to the characteristics of future residents and location.
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    Vehicle miles traveled and the built environment: New evidence from panel data
    (Journal of Transport and Land Use, 2020) Ihlanfeldt, Keith
    There has been considerable interest in the impact that the built environment has on vehicle miles traveled (VMT). While this issue has been extensively researched, due to the heavy reliance on cross-sectional data, there remains uncertainty regarding how effective local land-use planning and regulation might be in reducing VMT. Based on a 13-year panel of Florida counties, models are estimated that relate VMT to new measures of the spatial distribution of alternative land uses within counties and county urban expansion. Identification of causal effects is established by including year and county fixed effects, along with an extensive set of control variables, and instrumenting those land uses that may be endogenous. Incremental annual changes in the spatial concentration of alternative land uses are found to affect VMT. The policy implication is that appropriate land-use policy can reduce VMT and should be considered part of the strategy for dealing with the problem of global warming.