Causal Inference of Demand-Responsive Transit Implementation and Bridging Technology Adoption in Aging Societies
- 주제(키워드) Demand responsive transit , Bridging technology , Digital literacy , Causal inference , Spatial assessment , Accessibility
- 발행기관 아주대학교 일반대학원
- 지도교수 Eui-Jin Kim
- 발행년도 2026
- 학위수여년월 2026. 2
- 학위명 석사
- 학과 및 전공 일반대학원 D.N.A.플러스융합학과
- 실제URI http://www.dcollection.net/handler/ajou/000000035425
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Aging societies worldwide face mounting challenges in maintaining accessible public transportation, particularly in rural areas where demographic decline and dispersed populations render conventional fixed-route transit (FRT) economically unsustainable. Demand-responsive transit (DRT) has emerged as a flexible solution to improve mobility in such contexts. However, two critical gaps remain: First, how DRT introduction reshapes the overall public transportation system—comprising both DRT and FRT—has not been sufficiently explored. Second, while DRT promises enhanced accessibility, its reliance on smartphone-based booking creates digital barriers that paradoxically exclude older adults with limited digital literacy, the very population most dependent on public transportation. This dissertation addresses these gaps through a sequential evaluation framework that examines two interconnected interventions in rural Cheongju, South Korea. The first study analyzes how DRT implementation reshapes system-wide Public Transit (PT) demand patterns using causal impact inference based on Bayesian Structural Time Series (BSTS) models. The analysis employs residential clustering to construct spatial units that reflect realistic transit catchment areas, addressing the modifiable areal unit problem that biases conventional spatial analyses. Results indicate that approximately half of residents in the service area experienced significant increases in total PT usage of around 30%. DRT adoption was more beneficial in areas with lower population density, lower proportions of elderly residents, lower existing bus usage rates, and higher bus stop density. These findings suggest that DRT functions primarily as a complement rather than substitute for FRT, generating new demand through induced trips and modal shifts from private vehicles. Building on this DRT-enabled transportation system, the second study evaluates a bridging technology intervention designed to overcome digital access barriers: physical call buttons installed in senior centers that enable older adults to request DRT service through direct connection with customer service operators. Employing the same BSTS-based causal inference methodology, the analysis reveals that approximately 80% of service areas experienced significant increases in DRT trips following call button introduction. This growth reflects two mechanisms: increased use of both DRT and FRT services (indicating complementary effects), and additional DRT trips generated through modal shifts from non-public transit or newly induced demand. DRT trip growth was significantly associated with senior center density and distance to medical facilities, demonstrating that bridging technology effectiveness depends on strategic placement within social infrastructure networks frequented by target populations. The integrated findings demonstrate that inclusive rural mobility requires multi-layered interventions addressing both service flexibility (DRT) and access equity (bridging technologies). The sequential analysis reveals synergistic effects: call buttons proved effective precisely because DRT had established service reliability, while DRT reached its full accessibility potential only after call buttons removed digital barriers. Methodologically, the dissertation advances transportation research by developing a causal inference framework for evaluating sequential policy interventions and demonstrating how spatial analysis methods can account for the nested structure of accessibility improvements. These findings provide actionable insights for transportation planners in aging societies worldwide, emphasizing that technology-enabled transit innovations must be coupled with inclusive access mechanisms to serve all residents, particularly those least equipped to navigate digital interfaces.
more목차
Chapter 1 INTRODUCTION １
1. Research Background １
2. Research Motivation ２
3. Research Objectives and Questions ４
Chapter 2 CONTEXT ５
1. Key characteristics of DRT service and the Call button system ５
2. Integrated Structure of DRT-based PT system ６
3. Cheongju and DRT service area ８
4. Travel Patterns of Cheongju's PT system １０
A. Average Travel Distance １０
B. Departure Time Distribution １１
C. Spatial Distribution of DRT Origin-Destination Patterns １２
5. Hypothesis １５
A. Hypothesis of DRT implementation １５
B. Hypothesis of DRT Call Button Implementation １５
Chapter 3 LITERATURE REVIEW １７
1. Analysis of Demand-Responsive Transit Demand １７
2. Behavioral Nudging and Bridging Technologies １８
3. Mobility Accessibility Challenges for Older Adults １９
4. Causal Impact Inference ２０
Chapter 4 METHOD ２２
1. Analytical Framework Overview ２２
2. Data description and preparation ２４
A. Varo DRT Passenger Call Records ２５
B. Cheongju Fixed Route Bus Ridership Records ２８
C. Floor-level Building Use Data ２８
D. Socio-demographic Data ２９
E. Interregional Accessibility ３０
3. Residential cluster-based spatial unit ３０
4. Conceptual Framework: Demand Reshaping through Interventions ３３
A. Overview: Two-Level Demand Transformation ３３
B. Level 1: DRT Introduction Reshapes PT System ３４
C. Level 2: Call Button Introduction Reshapes DRT Access ３６
D. Classification of spatial clusters by changes in DRT and FRT Demand ３９
5. Causal Impact Inference using Bayesian Structural Time Series (BSTS) Model ４０
Chapter 5 RESULT AND DISCUSSION ４６
1. Result of Casual Impact of DRT (Level 1) ４６
A. Residents who experienced significant PT demand growth ４６
B. Changes in FRT and DRT trips accounting for PT demand growth ４９
C. Linear Regression on PT demand growth ５０
2. Result of Casual Impact of DRT Call Button (Level 2) ５４
A. Impact of call button on DRT and FRT ５４
B. Identifying induced/shift demand through call button adoptions ５８
C. Linear Regression on PT demand growth ６０
Chapter 6 CONCLUSION AND DISCUSSION ６２
1. Conclusion and discussions of implementation of DRT ６２
2. Conclusion and discussions of implementation of Call Button ６５
REFERENCES ６８
초록 ７５
