E. Willard and Ruby S. Miller Endowed Lecture at Penn State

I had the honor of giving the E. Willard and Ruby S. Miller Endowed Lecture in the Department of Geography at Pennsylvania State University on March 15, 2024. My talk was titled “Mapping Columbus’ Ghost Neighborhoods: Using AI and GIS to Create 3D Models of Neighborhoods Damaged by Urban Highways and Urban Renewal in the 20th Century.”

They even baked a cake!

The built environment and the determination of fault in urban pedestrian crashes: Toward a systems-oriented crash investigation

New paper: Stiles, J. and Miller, H.J. (2024) “The built environment and the determination of fault in urban pedestrian crashes: Towards systems-oriented crash investigation,”  Journal of Transport and Land Use, 17, 97-113.

Abstract: This study identifies built environmental factors that influence the determination of fault in urban pedestrian crashes in the United States, with implications for both safety and equity. Using data from Columbus, Ohio, we apply regression modeling, spatial analysis, and case studies, and find pedestrians are more likely to be found at fault on fast, high-volume arterial roads with bus stops. We also observe that better provision of crossings leads to more marked intersection crashes, which are less likely to be blamed on pedestrians. In addition, large differences in both the provision of crossings and fault exist between neighborhoods. We interpret findings through the lenses of the systems-oriented safety approaches Safe Systems and Vision Zero. The conclusion argues that the designation of individual responsibility for crashes preempts collective responsibility, preventing wider adoption of design interventions as well as systemic changes to the processes that determine the built environment of US roadways.

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Measuring the impacts of disruptions on public transit accessibility and reliability

New publication: Liu, L., Porr, A., and Miller, H.J. (2024) “Measuring the impacts of disruptions on public transit accessibility and reliability,” Journal of Transport Geography, 114, 103769.

Abstract. Public transit systems are facing higher risk of system degradation from external disruptions, affecting their ability to deliver reliable accessibility to transit users. Therefore, resilience, the ability to maintain functions during a disruption, becomes a crucial assessment of public transit systems. In this paper, we calculate two space-time prism-based measures with General Transit Feed Specification real-time (GTFS-RT) data: realizable real-time accessibility, a conservative real-time accessibility measure that can be achieved by users subject to delays, and scheduled accessibility, accessibility based on schedule. We also define accessibility unreliability, the deviation between realizable accessibility and scheduled accessibility, to measure the reliability of delivered accessibility. We use the two measures to gauge the resilience of public transit systems and conduct two case studies of short- and long-term disruptions, namely Ohio State football games and the COVID-19 pandemic, on the Central Ohio Transit Authority (COTA) bus system in Columbus, Ohio. We find there are two peaks of high unreliability before and after each football games, with the stadium as the geographic center of the disruption. The after-game peaks are shorter and more intense than the before-game. We also find COVID-19 had persistent negative impacts on accessibility and reliability: Realizable accessibility universally declined during the pandemic, but only part of cities experienced unreliability increase, primarily in urban perimeters and suburbs. Improved traffic conditions during the pandemic may help to reduce unreliability, but the later service cuts increased unreliability. The two case studies prove the effectiveness of the method to detect system disturbances and provide important guidance for public transit system operation and planning.

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