Investigating the Moderating Effects of Built Environment and Sociodemographics on Vehicle Ownership Using Latent Class Modeling
Sung Hoo Kim, Georgia Institute of Technology (Georgia Tech) Patricia Mokhtarian, Georgia Institute of Technology (Georgia Tech)
Show Abstract
Vehicle ownership (VO) is of vital interest to
transportation planning and policy, both in its own right and as a correlate of
other travel-related behaviors. This study explores disaggregate relationships
among socio-economic/demographic (SED) traits, the built environment (BE), and
VO. Many previous studies have assumed that the importance of SED and BE
variables is homogeneous across the population, and have focused on the direct
and mediated effects of those variables on VO. Here, we aim to account for
heterogeneity in the effects of BE and SED, allowing those effects on VO to be
moderated as a function of attitudes. Specifically, we use Latent Class Modeling
(LCM), which probabilistically segments the sample so as to be homogeneous
within and heterogeneous across segments, with respect to the choice process.
Applied to a sample of 2385 commuters in Northern California, LCM outperforms an
ordinary multinomial logit model and a deterministic segmentation model, and
produces meaningful results. We find that household size and income have
stronger influences on owning more vehicles for the “auto-oriented” segment than
for the “urbanite” segment. On the other hand, in general, urbanites are found
to be more affected by the BE than auto-oriented individuals are. This study
contributes to better understanding the heterogeneity of an important
travel-related choice process, offering another approach to addressing
residential self-selection.
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18-00682
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Does Urban Form Matter to Keep Seniors Active? Evidence from 23 Diverse Regions of the United States
Guang Tian, University of Utah Reid Ewing, University of Utah
Show Abstract
In most of the developed countries, the senior age group
has become the fastest growing demographic in the United States. The elderly
overwhelmingly want to “age in place” but cannot in the sprawling suburbs as
they lose the capability to drive. A good place for aging should have good
accessibility for the elderly and promote physical activity as a contributor to
overall health. In the face of an aging society, this study asks the following
questions: do seniors travel differently than younger adults and does the built
environment matter to keep seniors active? This study answers these questions by
using analysis of variance (ANOVA) and multilevel modeling based on a dataset
from 23 regions of the United States. The results shows that seniors with low incomes travel
less in total and travel more by public transit and walking than those with
higher income. Compared with those living in sprawling neighborhoods, seniors
living in compact neighborhoods generally travel more in total, and hence can be
deemed more active and mobile, which is a positive result as people age. They
also travel more by walking and public transportation, which is also a positive
result for their health. And they travel less by automobile as well, which is a
positive result for traffic safety as driving ability declines at advanced ages.
These findings provide support for policy making and planning processes that
encourage compact development in areas with large numbers of elderly or near
elderly populations.
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18-05674
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Longitudinal Cluster Analysis of Jobs–Housing Balance in Transit Neighborhoods
Robert Hibberd, University of Arizona Arthur Nelson, University of Arizona
Show Abstract
The jobs-housing balance is
a spatial problem. Fixed-guideway transit systems (FGT) are capturing jobs
across many metropolitan areas. Planners and policymakers have multiple
justifications for focusing on efforts towards balance. For example,
agglomeration economies, in large part the basis of metropolitan growth, benefit
from the alleviation of congestion. Additionally, urban resilience is enhanced
as workers can reduce transportation costs and utilize multiple modes of
transportation. Moreover, Location Efficiency (LE), the optimal configuration of
the built environment, is enhanced through job-worker balance. Transit systems
can aid in alleviating congestion and in balancing jobs and housing. This paper
presents a longitudinal study of spatial association of jobs, housing, and
transit systems in Chicago before, during, and after the Great Recession. As
workforce-housing balance is more indicative of internal capture, workers and
jobs are classified by income level and analyzed for degrees of global and local
spatial autocorrelation over time. The results show that LE transit
neighborhoods are populated in large part by high-income jobs and workers, and
this trend has continued in Chicago since the recession and during the years of
recovery. The overall change for all workers within a 2-mile band of both jobs
and transit was a gain of 13% from 2002 to 2009, and a loss of -47.3% from 2009
to 2014, while high-income workers lost proximity from 2009 to 2014 at a rate of
-4.7%. Policies are needed that aid workers of all income levels in enjoying the
benefits of LE and the increasing development of FGT systems.
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18-03557
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Millennials in Cities
Alexa Delbosc, Monash University Noreen McDonald, University of North Carolina, Chapel Hill Gordon Stokes, University of Oxford Karen Lucas, University of Leeds Giovanni Circella, Georgia Institute of Technology (Georgia Tech) Yongsung Lee, Georgia Institute of Technology (Georgia Tech)
Show Abstract
A recent explosion of research on the travel behaviour of
the millennial generation has found that compared to past generations they are
taking longer to get a driving license, driving less, owning fewer cars and
using public transport more. Yet these findings are not universal with
some countries seeing increases in driver licensing, little change in driving or
reductions in public transport use. Most past research has explored wider
social and economic explanations for these trends, such as income constraints
and delays in adult life transitions. Yet very few studies have examined
the role of the transport and land use system in explaining the change (or the
lack of change) in millennial travel behaviour. This paper aims to explore
the role of local context on trends in millennial travel behaviour. It
uses a comparative descriptive analysis of household travel surveys from six
regions in three countries (UK, USA and Australia), focussing on auto-miles and
transit-miles travelled. We find that economic and life stage factors do
not entirely account for the changes in travel behaviour among young
adults. There is preliminary evidence that changes to the transport
systems in these cities are also likely to be playing a role. We suggest
that further research should pay greater attention to the role of the transport
system in supporting changes to travel behaviour among the next generation of
young adults.
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18-03556
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