Research

Some of my research projects and publications are listed below. Also, You can find more information about my research on Google Scholar and ORCID.

Journal Articles

  1. Yin, Z., Rybarczyk, G., Zheng, A., Su, L., Sun, B., & Yan, X. (2024). Shared micromobility as a first- and last-mile transit solution? Spatiotemporal insights from a novel dataset. Journal of Transport Geography, 114, 103778. https://doi.org/10.1016/j.jtrangeo.2023.103778

    The first- and last-mile (FM/LM) problem is a major deterrent to public transit use. With the rise of shared micromobility options such as shared e-scooters in recent years, there is a growing interest in understanding their potential to serve as a last-mile transit solution. However, empirical data regarding the integrated use of shared micromobility and public transit have been limited so far. As a result, much is unknown regarding the spatiotemporal patterns and characteristics of shared micromobility trips serving as an FM/LM connection to transit. This paper addresses these knowledge gaps by leveraging a novel dataset (i.e., the Spin post-ride survey dataset) that records thousands of transit-connecting shared e-scooter trips in Washington DC. Specifically, we used the dataset to reveal the spatiotemporal patterns of transit-connecting shared e-scooter trips in Washington DC, resulting in some major policy insights regarding the integral use of shared e-scooters and public transit. We further leveraged the dataset to validate if and to what extent a commonly applied buffer-zone approach can infer FM/LM micromobility trips accurately. Statistical tests showed that the actual FM/LM Spin e-scooter trips differ from inferred FM/LM Spin e-scooter trips in both spatial and temporal dimensions. This indicates that the common practice of inferring FM/LM micromobility trips with a buffer-zone approach can lead to inaccurate estimates of transit-connecting micromobility trips.

  2. Huang, E., Yin, Z., Broaddus, A., & Yan, X. (2024). Shared e-scooters as a last-mile transit solution? Travel behavior insights from Los Angeles and Washington D.C. Travel Behaviour and Society, 34, 100663. https://doi.org/10.1016/j.tbs.2023.100663

    Shared e-scooters are quickly emerging in the U.S., presenting potential to enhance public transit by serving as a last-mile feeder mode. However, much is unknown about user preferences and travel behavior regarding e-scooter and transit integration. This study addresses this knowledge gap by conducting a travel behavior survey in Washington D.C. and Los Angeles, California, both early adopters of dockless micromobility. We find that the last-mile problem deters transit use for about 70% of respondents, among whom over 60% have considered e-scooters for last-mile transit connections. However, this intention frequently did not translate into actual use due to a variety of barriers. We further developed ordinal and binary logit models to examine factors shaping intention and actual use of shared e-scooters as a last-mile solution. Results suggest the outcomes of interest are positively associated with transit use frequency and safety rating of e-scooter riding. Somewhat surprisingly, household income is not a significant variable in all models. Women and older adults are less likely to consider using e-scooters as a last-mile feeder mode. People of color and individuals without a college degree who ride e-scooters have a greater percentage of their shared e-scooter trips made to connect with transit compared to White people and those with a college degree. These findings contribute to the understanding of equity in shared micromobility. Finally, to promote transit and micromobility integration, policymakers may introduce bundled fares, integrated payment, promote e-scooter safety, increase e-scooters availability at transit stops, and improve bike lane infrastructure connecting to transit.

Reports

  1. Forrister, A., Yan, X., Yin, Z., Zhao, X., Cova, T., Lovreglio, R., Nilsson, D., & Kuligowski, E. (2022). Survey of Evacuation Behavior in the 2021 Marshall Fire, Colorado. Natural Hazards Center Quick Response Grant Report Series, 349. Boulder, CO: Natural Hazards Center, University of Colorado Boulder. Available at: https://hazards.colorado.edu/quick-response-report/survey-of-evacuation-behavior-in-the-2021-marshall-fire-colorado

    Climate change is increasing the threat of wildfires to urban areas, especially those within the wildland-urban interface (WUI). The 2021 Marshall Fire forced the evacuation of 30,000 people and destroyed over 1,000 structures within Boulder County, Colorado. We conducted a survey with households affected by the grass fire to analyze their evacuation decision-making and travel behavior. The survey was based on previous surveys that members of our team developed to investigate the public response to the 2016 Chimney Tops 2 Fire in Tennessee and the 2019 Kincade Fire in California, but we have included new measures of transportation mode, route, and destination choices made by evacuees. We used linear and logistic regression models to determine the factors that influenced resident risk perception and the decision to evacuate and compared results from our analysis to the previous studies. We found significant variability in the factors that influenced risk perception and evacuation decisions across the three fires. The report also presents descriptive statistics to summarize our findings on evacuee travel behavior during the Marshall Fire.

Work in Progress

  1. What Makes People Happy with Their Neighbourhoods? Exploring Individual Covariates Beyond Socio-demographics in Scarborough, Ontario, with Shaila Jamal, and Steven Farber
  2. Towards sustainable neighborhoods? Tensions and heterogeneous transport priorities among suburban residents, with Ignacio Tiznado-Aitken, and Steven Farber
  3. Evaluating the Transit Accessibility and Equity of the Bus Rapid Transit (BRT) System: The Case of Dar-Es-Salaam, Tanzania, with Leonard Mwesigwa, and Steven Farber