2019

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.

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.

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.

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.