The Center for Advancing Research in Transportation Emissions, Energy and Health (CARTEEH) is hosting a webinar on April 16, 2025, with Dr. Fizzy Fan and Dr. Randall Guensler to discuss the health-related applications of the TransitSim 4.0 modeling tool.
Urban transit systems play a critical role in mobility, food access, and public health; however, traditional transportation models often lack the granularity needed to assess individual-level exposure to environmental conditions such as air pollutant concentrations and extreme heat/cold weather. Existing tools primarily rely on aggregated data, limiting their ability to capture the spatiotemporal complexity of transit experiences and their cumulative health impacts across user populations. In response to this gap, TransitSim 4.0 was developed to provide second-by-second trip trajectory data to support more detailed transportation analysis. TransitSim 4.0 integrates network analysis, graph theory, and a spatiotemporal modeling scheme to generate fine-grained transit user trajectories, allowing researchers and planners to analyze individual trip patterns, exposure risks, and system-wide transit dynamics.
This webinar will provide participants with the necessary training to utilize TransitSim 4.0 in applied research projects and transit use-case analyses. The webinar includes an overview, tutorials, and demonstrations of key functionalities. Attendees will explore how three real-world applications can be conducted using the model: 1) transit user exposure to traffic-related pollutants along different routes, 2) transit user cumulative heat/cold exposure and heat stress analysis (with reset recovery), and 3) transit user access to fresh food grocers across different user groups and sub-modes (e.g., wheelchair users). By the end of the session, participants will be equipped with the knowledge to integrate TransitSim 4.0 into their research and planning efforts, enabling a deeper understanding of transit-related health risks. The webinar will also include access to open-source tools and training materials, fostering broader adoption of high-resolution transit simulation in urban studies (Figure 1).
- Click here to download the webinar flyer.
- Click here to download a calendar invite.
- Click here to join the meeting.
Speakers:
Dr. Huiying (“Fizzy”) Fan
Georgia Institute of Technology
Fizzy Fan is a Research Engineer II at the Georgia Institute of Technology, specializing in spatiotemporal transportation resilience. Her research explores network-level dynamics, including trip-level risk accumulation, and cascading failures. She investigates the intersection of transportation and public health, with a focus on heat stress, air pollution, and food security, particularly among vulnerable populations. Dr. Fan develops individualized cumulative exposure models to advance environmental justice and inform policy interventions. Her work bridges theoretical insights with practical applications, leading to the development of simulation tools such as SidewalkSim and TransitSim, which support data-driven decision-making in transportation planning.
Dr. Randall Guensler
Georgia Institute of Technology
Randall Guensler is a Professor in the School of Civil and Environmental Engineering at the Georgia Institute of Technology. After working for the California Air Resources Board for seven years, and completing his Ph.D. in Civil Engineering at the University of California at Davis, Dr. Guensler joined Georgia Tech in 1994. During his years with the State of California, Dr. Guensler worked for four years in Compliance Assistance and for three years in the Executive Office, evaluating the design and implementation of transportation control measures by regional air quality management agencies. Since arriving at Georgia Tech, Dr. Guensler’s main research focus has been the development of new monitoring and modeling tools to assess the air quality impacts of transportation policies.
