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2025 Vol.43, Issue 6

Article

Analyzing the Effects of a Floor-type Pedestrian Signal Assist Device on Pedestrian Safety Using the Difference-in-Difference-in-Differences Method

삼중차분법을 이용한 바닥형 보행신호등 보조장치의 보행 안전 개선효과 분석

Bokyoung JEONG1
,
Hyeon NA1
,
Sugie LEE2*
정 보경1
,
나 현1
,
이 수기2*
1Master’s Degree, Department of Urban Planning and Engineering, Hanyang University, Seoul 04763, Korea
2Professor, Department of Urban Planning and Engineering, Hanyang University, Seoul 04763, Korea
1한양대학교 도시공학과 석사과정
2한양대학교 도시공학과 교수
*Corresponding Author
31 December 2025. pp. 699-715
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Abstract

This study examines the impact of a floor-type pedestrian signal assist device on pedestrian traffic safety in Seoul using the Difference-in-Difference-in-Differences(DDD) method. Furthermore, it aims to identify whether the effects of these devices differ between daytime and nighttime, with the goal of enhancing their practical effectiveness and contributing to the improvement of pedestrian environments. In light of growing concerns about “Smombie” (smartphone+ zombie)—pedestrians distracted by smartphone use—these devices have been introduced to improve pedestrian safety. However, empirical studies on their actual effectiveness in reducing pedestrian accidents remain limited. The study covers the periods from 2015 to 2017 (pre-installation) and from 2021 to 2023 (post-installation), with the unit of analysis set at 100-meter grid cells across Seoul. First, Propensity Score Matching was conducted to select comparable treatment and control groups and to confirm the parallel trends assumption. Subsequently, the difference-in-difference-in-differences method was applied to estimate the policy effect. The results show that the installation of floor-type pedestrian signal assist devices did not have a significant impact on reducing pedestrian accidents during the daytime. However, during nighttime, the devices were associated with a statistically significant decrease in accidents, suggesting a time-specific policy effect. This study contributes to the literature by providing empirical evidence on the effectiveness of floor-type pedestrian signal assist devices, offering policy implications for enhancing pedestrian safety.

Keywords
difference-in-difference-in-differences
floor-type pedestrian signal assist device
pedestrian safety
policy impact analysis
propensity score matching

본 연구는 삼중차분법을 활용하여 서울시를 대상으로 바닥형 보행신호등 보조장치가 보행자 교통안전 개선에 미친 효과를 확인하는 것을 목적으로 한다. 나아가, 주·야간에 바닥형 보행신호등 보조장치의 영향이 차이가 있는지 확인하며 본 보조장치의 실효성을 높이고, 보행환경의 발전에 기여하고자 한다. 최근 보행 중 휴대전화를 사용하는 사람들을 두고 스몸비(Smombie)라는 신조어가 등장할 만큼 보행안전 분야에서 그 심각성이 증가하고 있다. 바닥형 보행신호등 보조장치는 이러한 스몸비족의 보행안전에 도움을 주기 위해 도입되었으나, 해당 보조장치가 실제로 보행자 교통사고 감소에 효과가 있는지에 관한 실증연구는 부족한 실정이다. 본 연구의 시간적 범위는 2019년 바닥형 보행신호등이 도입되기 전후 3년인 2015년부터 2017년까지, 2021년부터 2023년까지이다. 공간적 범위는 서울시이며 분석 단위는 100m 격자로 설정하였다. 먼저 성향점수매칭을 실시하여 처치군과 대조군을 선정해 평행추세가정을 확인 후, 삼중차분법을 적용해 정책 효과를 분석하였다. 분석 결과, 바닥형 보행신호등 보조장치의 설치는 주간 시간대 보행자 교통사고 건수 감소에 유의미한 영향이 나타나지 않았으나, 야간 시간대의 경우 사고 건수 감소에 유의한 영향을 미친 것으로 나타났다. 본 연구는 바닥형 보행신호등 보조장치의 효과를 실증적으로 분석하여 보행자 안전에 대한 정책적 시사점을 제시하였다는 점에서 의의가 있다.

키워드
삼중차분법
바닥형 보행신호등 보조장치
보행안전
정책 효과 분석
성향점수매칭
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Information
  • Publisher :Korean Society of Transportation
  • Publisher(Ko) :대한교통학회
  • Journal Title :Journal of Korean Society of Transportation
  • Journal Title(Ko) :대한교통학회지
  • Volume : 43
  • No :6
  • Pages :699-715
  • Received Date : 2025-06-13
  • Revised Date : 2025-07-30
  • Accepted Date : 2025-09-04
  • DOI :https://doi.org/10.7470/jkst.2025.43.6.699
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