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Realizable accessibility: evaluating the reliability of public transit accessibility using high-resolution real-time
Luyu Liu1, Adam Porr1, Harvey J Miller1
1Department of Geography and Center for Urban and Regional Analysis, The Ohio State University, 1036 Derby Hall/154 N Oval Mall, Columbus, OH 43210 USA.
Journal of Geographical Systems
|May 26, 2022
Summary
New transit accessibility measures account for real-world delays, offering a more realistic assessment of access to jobs and healthcare. This approach improves transit planning by reducing overestimations inherent in traditional methods.
Area of Science:
- Urban Planning
- Transportation Geography
- Geographic Information Systems (GIS)
Background:
- High-resolution public transit data enhances accessibility analysis for community resources like jobs and healthcare.
- Traditional methods using schedule data overestimate accessibility due to unaddressed bus delays.
- Existing real-time measures still overestimate accessibility by assuming perfect rider information.
Purpose of the Study:
- Introduce realizable real-time accessibility using space-time prisms for a more conservative measure.
- Define accessibility unreliability to quantify overestimation in traditional accessibility metrics.
- Evaluate the effectiveness of these new measures in a real-world transit system.
Main Methods:
- Developed realizable real-time accessibility based on space-time prisms.
- Defined accessibility unreliability to quantify overestimation.
- Utilized high-resolution General Transit Feed Specification (GTFS) real-time data for analysis.
- Conducted a case study on the Central Ohio Transit Authority (COTA) bus system.
Main Results:
- Realizable accessibility proved to be the most conservative measure among the three evaluated.
- Identified spatial and temporal patterns in the unreliability of schedule-based and retrospective accessibility.
- Observed patterns in unreliability align with known spatial and temporal patterns of bus delays and missed transfers.
Conclusions:
- Realizable real-time accessibility offers a more practical, conservative, and robust approach for transit planning.
- Accessibility unreliability metrics effectively highlight overestimations in conventional accessibility measures.
- Findings support the need for advanced accessibility metrics that incorporate real-time transit performance.
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