Publications, Department of Geography and Geoinformation Science

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Browsing Publications, Department of Geography and Geoinformation Science by Author "Ermagun, Alireza"

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    An Introduction to Applications of Access
    (Network Design Lab, University of Sydney, 2021) Ermagun, Alireza; Levison, David
    From its source Latin accedere, the assimilated form of ad and cedere, access means "to approach." It conveys the "habit or power of getting into the presence of someone or something." The contemporary meaning differs, but has not strayed too far from the origin. Access means freedom, possession rights, and other means of benefiting from resources. It offers neither what people will do, nor what people want to do, rather what people could do. Transport access is a product of mobility and place and immediately relates to the transport network and the relative location of human activities and housing. However, there is still confusion among engineers and planners in differentiating access from mobility. Mobility indicates one’s ability to move easily. It encompasses both speed and travel time by defining how far one can travel in a given time. Access, however, is concerned with the opportunities that can be reached in a given time.
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    Transit Access Performance Across Chicago
    (Network Design Lab, University of Sydney, 2021) Janatabadi, Fatemeh; Tajik, Nazanin; Ermagun, Alireza
    This chapter studies the spatial and temporal disparity of modal access to employments by measuring the Modal Access Gap (MAG) in Chicago and its nine neighborhoods. Access to employment is calculated for transit, auto, and walk in twelve 5-minute travel time thresholds at the Census block group level. First, a gradual reduction in MAG can be seen in Chicago and across its neighborhoods with an increase in travel-time thresholds. Second, different neighborhoods, depending on their proximity and distance from the Central Business District (CBD), display distinct MAG variations. The modal access gap, therefore, should not be measured in isolation of the spatial and temporal dimensions of the transit service. Third, assigning a single MAG score to the city at a specific travel-time threshold describes the city transit system imprecisely. Comparing transit and walk, the city MAG value inclines toward portending higher transit efficiency for its subareas. While comparing transit and auto, the city MAG suggests an inferior transit performance compared to the neighborhoods' average. This chapter informs urban planners and policymakers of the effects of travel time and space on access analysis. Inaccurate perceptions of transit performance prevent the development of an efficient and equitable transit system.