Date of Award

December 2019

Document Type


Degree Name

Doctor of Philosophy (PhD)


Planning, Development, and Preservation

Committee Member

Eric A. Morris

Committee Member

William C. Bridges

Committee Member

Luis E. Ramos-Santiago

Committee Member

Lu Shi


Millions of Americans have difficulties in transporting themselves to desired locations and thus are considered to be transportation disadvantaged (Wallace, Hughes-Cromwick, Mull, & Khasnabis, 2005). This population group is found to participate in fewer out-of-home activities, which may eventually result in social exclusion and impaired well-being (Kenyon, Rafferty, & Lyons, 2003; Marottoli et al., 2000). This research examines one critical aspect that is important for people’s well-being—healthcare access. Despite the effort and resources the government has put into improving healthcare access, impaired access remains a problem in the United States (Department of Health and Human Services, 2010). Transportation disadvantage has been reported as one key barrier to healthcare access (Arcury, Preisser, Gesler, & Powers, 2005).

Building on social exclusion theory, this dissertation examines the impact of transportation disadvantage, including limited mobility due to a lack of access to transportation resources and long travel times to usual source of care, on healthcare access among non-institutionalized adults in the United States with the use of secondary data from the National Health Interview Survey (NHIS) and the Medical Expenditure Panel Survey (MEPS), two national surveys that report on healthcare access, health status, healthcare expenditure, and other health-related information.

To be more specific, I use data from the NHIS 1993-1996 to examine the impact of vehicle ownership on healthcare access, which is measured by whether or not one has a usual place that is not a hospital emergency department (ED) for medical care, and whether or not one has forgone needed medical care in the last 12 months. Those who have no vehicle in the family are considered to be transportation disadvantaged. By using logistic regression models to perform cross-sectional analysis, this study finds that owning a vehicle in the family is associated with higher odds of having a non-ED place for usual source of care and with lower odds of having forgone needed medical care, when demographic, socio-economic and health characteristics are controlled for. I also use data from Panel 5 of the MEPS 2000-2001 to examine the impact of transportation mode (including driving or being offered a ride, using public transit, and walking) on the likelihood of any family member having difficulties in obtaining needed care. Random-effects logistic regression is used to perform longitudinal data analysis. The results show that having access to a car and having access to public transit are associated with decreased odds of any family member having experienced difficulty in getting care. But no significant difference is found between car users and public transit users.

The above three analyses also include the “metropolitan residence” (i.e., whether a person lives in a Metropolitan Statistical Area, in the central city or not, or does not live in an MSA). Given the assumption that healthcare resources are widely dispersed in areas outside an MSA and that the spatial distances between healthcare users and healthcare providers are likely to be greater in non-Metro areas than in the urban areas, the results of metropolitan residence are suggestive of the impact of spatial distance on healthcare access. In this sense, the results suggest no clear evidence that spatial distance plays an important role in preventing people from accessing healthcare: people who live outside an MSA are found to be more likely to have a non-ED place for usual source of care and to be less likely to have forgone needed care in the past 12 months than people who live in the central city in an MSA; also, no significant difference is found in the likelihood of any family member experiencing difficulty in getting care between those living in an MSA and the ones living outside an MSA. However, it should be noted that the assumption does not always hold true. It is possible that living in areas outside an MSA does not necessarily mean residing farther away from healthcare resources. Also, the results of “metropolitan residence” illustrate the disparity in healthcare access between MSAs and areas outside MSAs, which may result from the combined effect of spatial distance and other factors that also differ significantly between these areas. Therefore, using only the spatial distance to interpret the healthcare access disparity may cause bias.

Next, I focus on the NHIS respondents who reported that they have delayed getting needed care because of a lack of transportation (referred to as transportation deficiency) in the past 12 months. By pooling data from the NHIS 2007-2018, I use logistic regression to examine the disparities in experiencing transportation deficiency among different population groups. The results show that being female, being non-Hispanic African American, being American Indian/Alaska Native, being multiple race, being Hispanic (any race), being unemployed or not in the labor force, having some activity limitations, having never been married, being divorced/separated, and being widowed are associated with increased odds of having experienced transportation deficiency. I also examine the impact of transportation deficiency on the type of usual source of care among adults with a usual source of care. The type of usual source of care includes a doctor’s office or health maintenance organization, clinics or health centers, hospital outpatient department, hospital emergency department (ED), and other places; those who reported using an ED as usual source of care are considered to have poor healthcare access. Multinomial logistic regression is used for cross-sectional data analysis. The results show that adults who experienced transportation deficiency in the last 12 months are more likely to use an ED than to use other medical resources as their usual source of care, compared with adults who did not experience transportation deficiency.

Lastly, I use data from the MEPS 2002-2016 to analyze the impact of travel time to the usual source of care on the experience of having delayed or forgone needed care in the last 12 months. Random-effects ordered logistic regression is used to perform longitudinal analysis. The results show that when people need to travel more than 30 minutes to their usual source of medical care, the odds of having experienced delayed care or having experienced forgone necessary medical care are expected to increase.

In sum, the results of this dissertation reveal a significant impact of mobility (access to transportation resources) and travel time on healthcare access. Although it cannot be proven, the results are suggestive that there is no clear evidence that spatial distance plays an important role in preventing healthcare access. Based on the findings, policies that help improve people’s access to transportation resources are discussed. In particular, facilitating automobile ownership by supporting nonprofit organizations that promote affordable car ownership programs and relaxing welfare asset test limits for the low-income, using ridehailing services, developing public transit services in urban areas, developing more transportation programs such as nonemergency medical transportation (NEMT), and using telecommunication technologies to deliver healthcare are discussed.



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