Congratulations to our 2025 Dissertation Grant Awardees!
Congratulations to our recent dissertation grant awardees out of UC Davis! These six awardees are researching everything from digital transportation platforms to global supply chains to changes in public transit!
Maha Ahmad | Transportation Technology and Policy, UC Davis
NCST Dissertation Grant
Public transit has suffered from chronic disinvestment despite its community-wide benefits. Drastic changes in travel demand over the last few years have left agencies grappling with financial stress. California’s transit ridership has generally tracked alongside national ridership trends with a substantial dip in ridership and then slow recovery, but commuter rail mode share has remained substantially lower. Maha’s dissertation will use survey research to inform how to tailor rail services to gain new markets. A stated preference experiment was developed to understand evolving needs of commuters and non-commuters, as well as riders and potential riders.
The results of Maha’s study can be used by Capitol Corridor to tailor its service to better suit the needs of its customer base. The survey instrument is planned to be published so that other transit agencies can design a similar survey to conduct in their region. The results may also inform policy decisions at the state and federal level. On a broader level, the results may shed light on the real preferences of potential regional rail riders and whether passenger rail would be adopted more frequently if better options were available.
Tak Chun "Marcus" Chan | Transportation Technology and Policy, UC Davis
NCST Dissertation Grant
Mobile ticketing apps have become increasingly popular among transit agencies due to their cost-effectiveness and ability to streamline payments. These apps also generate vast travel data with the potential to support transit agencies in decision-making. However, this data contains incomplete trip information and may suffer from representation bias. Marcus’ research will address this gap by evaluating the potential applications and representativeness of mobile ticketing data through the use of ZipPass–a mobile ticketing app used by Unitrans in Davis, California. Marcus plans to conduct a targeted survey of active ZipPass users to supplement their trip history with rider-specific and trip-level information.
Marcus’ project will give transit agencies a low-cost way to use mobile ticketing records for stop-level ridership estimates and basic origin–destination insights. It will also show whether app users represent the full rider population and identify the factors that shape both adoption and frequency of use. The modeling tools and data workflows can be used directly by Unitrans, as well as other transit agencies, to improve service planning without the need for an expensive automated fare collection system. Overall, the work is expected to support clearer demand estimates, smoother operations, and more reliable and economical transit service.
Juan C. Lopez Restrepo | Civil and Environmental Engineering, UC Davis
NCST Dissertation Grant
Global supply chains continue to face multiple disruptions that impact the economies of countries and regions. Juan’s dissertation research proposes a data-driven resilience framework that monitors emerging and evolving disruptions and identifies their effects on freight operations and supply chains. The work will also identify critical freight infrastructure in California exposed to natural hazards, and evaluate the impact of these hazards on the flow of goods in the State.
Such methodology and outputs are designed to be replicable in other States, where they can guide decisions on resilient infrastructure investments and freight-oriented long-term planning.
The tools produced in Juan’s work will enable Caltrans and other agencies to develop strategic plans for the freight system (e.g., investment in critical infrastructure,the use of hazard-resistant materials, or added redundancy in specific sections of the network). The resulting framework is expected to improve the resilience of California’s freight system. Over time, these outputs can help maintain the continuity of goods movements and mitigate the economic impact of disruptions for businesses and individuals.
Claire McGinnis | Transportation Technology and Policy, UC Davis
NCST Dissertation Grant
Accessibility is an important concept in transportation that has garnered an extensive amount of research. However, there has not been a consensus on a singular best practice of measuring accessibility. Claire’s dissertation research will contribute to the literature on perceived accessibility, which sheds light on individual differences that typical accessibility measures do not account for. It is important to understand how perceptions of safety and accessibility may influence mode choice and ability to access economic opportunities.
Ultimately, Claire’s research aims to deepen understanding of the subjective elements of accessibility: how people interpret their travel environment, how these perceptions influence their travel decisions, and how different population groups may experience accessibility in distinct ways. These insights can help refine accessibility-based planning approaches and support improved measurement of how people navigate and engage with their transportation environment.
Maria Catalina Valencia-Cardenas | Transportation Technology and Policy, UC Davis
NCST Dissertation Grant
Growth in e-commerce, supply chain restructuring, and regional economic development incentives have contributed to an uneven and largely uncoordinated proliferation of freight facilities. Although these facilities support regional economies, their concentration heightens concerns about congestion, safety, air quality, and the quality of jobs they bring. Local and regional governments struggle to anticipate these impacts because they lack empirical tools to link policy actions to freight facility siting decisions.
Maria’s dissertation research develops an integrated framework to evaluate how land-use, transportation, and economic development policies influence the location of freight facilities in California, and how these siting patterns shape labor and mobility outcomes in surrounding communities. The research will contribute to a more efficient and resilient transportation system, support evidence-based freight and industrial land-use regulation, and improve understanding of how logistics clusters influence regional economic performance and labor conditions.
Yunwan Zhang | Transportation Technology and Policy, UC Davis
NCST Dissertation Grant
Digital transportation platforms are increasingly used to coordinate multimodal travel and streamline fare payment, thereby improving efficiency for both operators and passengers. Using data from the Vamos mobility system in Stockton, California, Yunwan’s research combines app telemetry, Uber trip records, mobility incentive transaction data, survey data, and General Transit Feed Specification (GTFS) data to examine how credits and ridehailing integration affect platform engagement, transit and Uber use, first/last-mile connectivity, temporal usage patterns, and destination reach. Yunwan’s work will contribute empirical evidence on multimodal coordination from an operational Mobility-as-a-Service platform. Further, the research will provide a methodological framework to help agencies analyze observed travel behavior data.
Future findings will inform the development of digital mobility tools, integration strategies with ridehailing providers, and incentive structures aimed at improving multimodal connectivity and system performance. Stop-level results can support targeted operational improvements, such as feeder service planning, pickup-zone placement, and schedule adjustments, to strengthen multimodal efficiency.