Jinhyung Lee

Bio: Jinhyung Lee is an academic researcher from Ohio State University. The author has contributed to research in topics: Bus rapid transit & Public transport. The author has an hindex of 6, co-authored 8 publications receiving 93 citations.

Analyzing collective accessibility using average space-time prisms

Abstract: The space-time prism (STP) is the envelope of all possible travel paths in space and time between two anchor locations and times, measuring accessibility for an individual given a designated travel and activity episode. Although the STP provides a powerful measure of individual accessibility, transportation researchers often need to analyze accessibility at collective-levels for planning and policy analysis. Deriving a representative STP of a set of individual STPs would provide a general idea of how collective members’ accessibility is performing. However, there is no analytical time geographic method to calculate a collective-level representative STP that is consistent with individual STPs. To fill this gap, this research develops the concept of average space-time prism (ASTP). The ASTP is a representative STP of a group of individual STPs with respect to size, shape, and location. We develop methods for calculating an ASTP using analytical time geography and elliptic Fourier shape analysis techniques. The ASTP provides a geometric and visual summary of collective accessibility: it can be used to generate representative STPs for aggregate geographic units such as neighborhoods and cities based on individual-level data. A possible application of the ASTP is the spatial equity analysis of accessibility. The ASTP can be located at individuals’ anchor locations and overlaid with opportunities, enabling in-situ comparisons between individual versus collective accessibility and accessibility equity analysis considering geographic contexts. We illustrate this ASTP’s capability when measuring the impacts of new transit service on healthcare access equity in a neighborhood in Columbus, Ohio, USA.

Measuring the Impacts of New Public Transit Services on Space-Time Accessibility

Abstract: Abstract The absence of effective access to opportunities and services is a key contributor to poor socio-economic and health outcomes in underserved neighborhoods in many cities. The city of Columbus, Ohio, USA is attempting to enhance residents' accessibility by providing new public transit services. These new services include a major Transit System Redesign (TSR) of the conventional bus network and the introduction of a new bus rapid transit, named CMAX. Using a high-resolution space-time accessibility measure, we analyze whether these new public transit services will change residents' accessibility to job and healthcare in an underserved neighborhood of Columbus. Also, we assess whether enhancing the CMAX service to reduce delays (e.g., reserved lane, off-board payment system) will improve accessibility. The high-resolution space-time accessibility measure in this study uses published public transit schedules via the General Transit Feed Specification (GTFS). We use multiple departure times during a day to account for the temporal fluctuations of accessibility based on the transit schedule changes. We also consider the operating hours of job opportunities and healthcare services. Results suggest that the TSR yields ambiguous benefits for accessibility to jobs and healthcare. However, the new CMAX service and its potential upgrades lead to a substantial increase in both job and healthcare accessibility. The results can be used for city officials and urban planners to evaluate the effectiveness of public transit innovations in improving accessibility.

Towards a contemporary perspective of retail location

Abstract: Much of the existing literature on location does not address the problems faced by retail organizations at a strategic level, largely because it has tended to concentrate on the technical and policy issues relating to the evaluation and development of new sites. The reason for this lies largely in the geographic origins of most previous work, and while marketing has borrowed many of these concepts and approaches, it has not yet fully developed additional ones appropriate for a strategic management audience. Reviews research in the geography and marketing traditions, and builds on recently published work to outline two new conceptual models which serve to link strategic and monadic (individual site) decisions. Discusses the development of a more holistic perspective which underlines the strategic role of retail location and emphasizes key areas for research relevant to many of the issues currently facing retail organizations.

Variation in Bus Transit Service: Understanding the Impacts of Various Improvement Strategies on Transit Service Reliability

Abstract: Transit agencies wishing to offer reliable service with less variability face several challenges, encouraging them to employ various strategies. While previous research has considered the effects of various strategies on running time, there has been little effort to understand their impacts on reliability of service. This article examines the impacts of various improvement strategies on running time deviation from schedule, variation in running time, and variation in running time deviation from schedules. These strategies include implementation of a smart card fare collection system, operation of a reserved bus lane, introduction of limited-stop bus service, use of articulated buses, and operation of transit signal priority (TSP). This study conduct this examination using data obtained from the Societe de Transport de Montreal (STM)’s automatic vehicle location (AVL) and automatic passenger count (APC) systems, in Montreal, Canada, at the bus route segment level of analysis. The introduction of a smart card fare collection system increased bus running time and service variation. Articulated buses, limited-stop bus service and reserved bus lanes have mixed effects on variation in comparison to the running time changes, while TSP did not show an impact on variations in our study. This study offers transit agencies and schedulers a better understanding of the effects of various strategies on different aspects of service variation, which are important components of transit service reliability.