Transportation System Performance and Traveler Behavior in the Context of a Systemwide Shock: Applications of Data Science Toward a Sustainable Future

The COVID-19 pandemic, a systemwide shock, has left a long-lasting and significant impact on transportation systems. It has contributed to a shift in travel behavior, with many people turning to work from home (WFH) and online shopping. This shift has led to a reduction in vehicular travel. However, the pandemic witnessed increased crash fatalities despite a reduction in overall crashes, disproportionately affecting disadvantaged communities (DACs). The main question arising from these pandemic-related issues is what we can learn to improve transportation systems and shape future travel behavior. Therefore, this dissertation aims to investigate how the transportation system changed during COVID-19 and explore the future implications while examining the travel behavior, technology adoption behavior, and road safety aspects in DACs compared with non-DACs during COVID-19. As such, this dissertation first explores the interaction between WFH, online shopping, and in-person shopping behaviors, revealing nuanced relationships that have evolved amidst the pandemic. Second, comprehensive safety data are utilized to dissect why crash fatalities increased during COVID-19. Third, transportation safety in DACs is investigated by leveraging safety data covering COVID-19 periods and the comprehensive DAC indicators developed by the US Department of Transportation. Fourth, DACs’ shopping behavior during COVID-19 is analyzed by focusing on the interplay of emerging online delivery components (retail, grocery, and food) and in-person activities. Finally, the study compares technology adoption behaviors between DACs and non-DACs by exploring infrastructure and socio-economic barriers. Methodologically speaking, this dissertation employs various state-of-the-art statistical and explainable artificial intelligence techniques. Overall findings indicate that compared to pre-COVID-19, the surge in WFM and e-commerce trends was associated with a substantial reduction in physical shopping trips during COVID-19. Speeding and reckless behaviors were strongly associated with the increased road fatalities. DACs experienced heightened adversity than non-DACs, associated with a higher rate of fatal crashes (an increase of 8% to 57%). Online orders were considerably less frequent in DACs than non-DACs (2% to 7%), emphasizing disparity in digital infrastructure. Additionally, technology adoption rates were significantly lower in DACs. These findings underscore the importance of better preparedness and planning for such communities to be equipped to handle future systemic shocks

Efficiency Studies of the US Transportation Sector

Transportation builds the economy by moving people and goods. The transportation systems and their networks are growing very rapidly to smoothen the overall traffic flow. It also has resulted in increased energy use, traffic congestion, pollutions, and land-use change. US airports play an important role in the nation’s economic growth. The deregulation process of US aviation in 1978 has led airlines and airports to be more dynamic and competitive through economies of scale and rapid adaption to technological changes. However, in recent years, many airports lack dedicated infrastructure investment. They are experiencing outdated facilities and crowded terminals. They are operating beyond their capacity. Furthermore, there are negative externalities such as, flight delays, pollutions generated because of the operation of US airports. The U.S. freight sector also has continued to expand over the past decades and made a key role in linking the nation’s economic activities. In 2018, nearly 5.3 trillion ton-miles of goods were moved in the nation with trucks as the dominant mode. The increase of road freight transport presumably maintains given the surging development of eCommerce and easiness of online shopping. Such growth in the freight demand likely increase the fuel used in the road freight and result in more greenhouse gas (GHG) emissions. Therefore, it is important to make sure the system is efficient to reduce energy use and related pollutions, and to save congestion/delay time, and operating costs. Therefore, efficiency analysis in transportation problems has gained considerable research attention in the past two decades. The overall aim of this study is to determine the efficiency of two major transportation services, airports, and road freight, in the United States. The operational efficiency of the 50 US airports in 2009-2018 is analyzed by considering local air pollutions and flight delays as undesirable outputs, and related carryover activities (such as debt, expenditure, and use capital) to account for the linkage of consecutive periods. Further investigation examines the factors that could explain the variation among airport efficiency. The results indicate that it is crucial to include carryovers and undesirable outputs into consideration when analyzing the efficiency of airports. We found that medium airports perform better with the undesirable outputs/ carryovers’ inclusion. Some inefficient airports have improved their operations to reach the efficient frontier over time, while a smaller number remained inefficient given the years. We found that the efficiency of the US airports depends on the hub size, population density, GDP, international share of flights, fleet size, and local workforce. We also analyze the rebound effect generated from the energy efficiency improvement in the US road freight transport including under asymmetric energy price responses. Our results suggest that the rebound effect exists in US road freight transport and that the effect has increased in recent years. We also found that the rebound effect increases with decreases in energy price and decreases with energy price increases. Important policy implications of the findings have been discussed