All Issue

2026 Vol.44, Issue 4

Article

Impact of Voluntary Older Driver’s License Surrender on Traffic Crashes: Continuous Difference-in-Differences Analysis

연속형 이중차분법을 이용한 고령자 운전면허 자진반납에 따른 교통사고 영향 분석

Won Ho KIM1
,
Hyerim CHO2
,
Sangmi JEONG3
,
Sangshin KIM4
,
Youngje JEONG5*
김 원호1
,
조 혜림2
,
정 상미3
,
김 상신4
,
정 영제5*
1Chief Director, Smart Transportation Research Lab, The Seoul Institute, Seoul 06756, Korea
2Chief Director, AI&BigData Lab, The Seoul Institute, Seoul 06756, Korea
3Researcher, Smart Transportation Research Lab, The Seoul Institute, Seoul 06756, Korea
4Director, Transportation Operation Division, Seoul Metropolitan Government, Seoul 04525, Korea
5Research Fellow, Smart Transportation Research Lab, The Seoul Institute, Seoul 06756, Korea
1서울연구원 스마트교통연구실 선임연구위원
2서울연구원 AI빅데이터랩 선임연구위원
3서울연구원 스마트교통연구실 연구원
4서울특별시청 교통운영과 과장
5서울연구원 스마트교통연구실 연구위원
*Corresponding Author
31 August 2026. pp. 497-510
PDF XML Citation
Abstract

This study analyzes the statistical association between Seoul’s voluntary driver’s license surrender program for older drivers and the reduction in traffic crashes, providing empirical evidence for the program’s potential policy contributions. To identify this relationship, an older-driver crash rate prediction model was constructed by applying the continuous difference-in-differences (DID) approach, which allows for a comparison of policy intensity differences within the treatment group. Panel data from 2015 to 2024 were established using Seoul’s older-driver traffic crash and license surrender records, organized by year, region, and age group. The older-driver crash rate was specified as the dependent variable, while the license surrender rate and the non-older-driver crash rate were included as independent variables to confirm the correlation under conditions controlled by the non-older-driver crash rate. The results indicate that the coefficient of the license surrender rate is −0.02142, suggesting a statistical trend where a 1%p increase in the surrender rate is associated with a 0.02142%p decrease in the older-driver crash rate. Based on Seoul’s 2024 older-driver traffic crash data, this is interpreted as a potential scale corresponding to a reduction of approximately 102 crashes for every 1%p increase in the license surrender rate. Subgroup analyses by age group demonstrate an age-incremental trend, where the association between license surrender and crash reduction becomes more pronounced as age increases. These findings suggest that the voluntary license surrender program functions not merely as a welfare-oriented support measure but as a contributing factor to older-driver traffic safety, providing foundational data for a limited causal interpretation.

Keywords
continuous difference-in-differences
license surrender rate
non-older driver crash rate
older driver crash rate
voluntary license surrender for older drivers

본 연구에서는 서울시 고령자 운전면허 자진반납제도와 교통사고 감소 간의 통계적인 연관성을 분석하고, 정책적 기여 가능성에 대한 실증적 근거를 제시하였다. 고령자 운전면허 자진반납제도와의 연관성을 확인하기 위해 면허반납률 변화와 고령자 사고율과의 관계를 분석했으며, 이를 위해 처치집단 내부의 정책강도 차이를 비교할 수 있는 연속형 이중차분법(Continuous Difference-in-Differences)을 적용해 고령자 사고율 예측모형을 구축하였다. 2015년부터 2024년까지의 서울시 고령자 교통사고 및 면허반납 데이터를 이용하여 연도·권역·연령별 패널데이터를 구축하였고, 고령자 사고율을 종속변수로 면허반납률과 비고령자 사고율을 독립변수로 설정해 비고령자 사고율로 통제된 조건에서 면허반납률과 고령자 사고율의 상관성을 확인하였다. 분석 결과 고령자 사고율을 결정하는 면허반납률의 계수는 –0.02142를 나타내었으며, 면허반납률 1%p 증가 시 고령자 사고율은 0.02142%p 감소하는 통계적 경향성이 관찰되었다. 2024년 서울시 고령자 교통사고를 기준으로 면허반납률 1%p당 102건의 고령자 사고 감소와 연관될 수 있는 잠재적 규모로 풀이된다. 연령대별 서브그룹 분석 결과, 면허반납과 사고 감소 간의 연관성은 연령이 높아질수록 뚜렷해지는 점증적 경향을 보였다. 이러한 분석 결과는 고령자 면허반납정책이 복지성 지원에 머무르는 것이 아니라, 고령자 교통안전 정책으로서 기여할 수 있음을 시사하는 제한적 인과해석의 기초자료를 제공한다.

키워드
연속형 이중차분법
운전면허 반납률
비고령자 사고율
고령자 사고율
고령자 운전면허 자진반납
References
1

AAA Foundation (2023), Older Driver Licensing Policies and Practices Database, Washington, DC: AAA Foundation.

2

Angrist J.D., Pischke J.S. (2009), Mostly Harmless Econometrics: An Empiricist’s Companion, Princeton University Press.

10.1515/9781400829828
3

Borsati M., Cascarano M., Bazzana F. (2019), On the Impact of Average Speed Enforcement Systems in Reducing Highway Accidents: Evidence From the Italian Safety Tutor, Economics of Transportation, 20, 100123.

10.1016/j.ecotra.2019.100123
4

de Chaisemartin C., D’Haultfœuille X. (2020), Two-Way Fixed Effects Estimators With Heterogeneous Treatment Effects, American Economic Review, 110(9), 2964-2996.

10.1257/aer.20181169
5

Elvik R. (2024), A Comparative Analysis of Accident Modification Functions for Traffic Law Enforcement, Accident Analysis & Prevention, 195, 107415.

10.1016/j.aap.2023.107415
6

European Commission (2023), Assessing the Fitness to Drive, Available at: https://road-safety.transport.ec.europa.eu/eu-road-safety-policy/priorities/safe-road-use/elderly-drivers/older-drivers/what-can-be-done-about-it/assessing-fitness-drive_en (Accessed: 1 May 2025).

7

Hong D., Han S. (2024), Impact of Elderly-Caused Crashes After Voluntary Driver’s License Return, J. Korean Soc. Transp., 42(4), Korean Society of Transportation, 398-407.

10.7470/jkst.2024.42.4.398
8

Korean National Police Agency (2025), Driver’s License Administration Statistics (운전면허통계), Seoul: Korean National Police Agency.

9

Lee D.Y., Hong D. (2024), Analyzing the Impact of Voluntary License Return on Traffic Crash Types Involving Elderly Drivers, Int. J. Highw. Eng., 26(6), Korean Society of Road Engineers, 251-261.

10.7855/IJHE.2024.26.6.251
10

Moon S., Park S. (2019), Evaluating the Impact of Voluntary Driver's License Surrender on Traffic Accidents Among Older Drivers: Evidence From Busan, Proceedings of the 2019 Statistics Korea Paper Competition, Daejeon: Statistics Korea, 206-227.

11

NLI Research Institute (2020), Has Voluntary Driver's License Surrender Among Older Adults Increased? (高齢者の運転免許返納は増加したか？), Tokyo: NLI Research Institute. Available at: https://www.nli-research.co.jp/report/detail/id=64131 (Accessed: 1 May 2025).

12

Road Safety Authority (RSA) (2025), Medical Fitness to Drive Guidelines, Dublin: Road Safety Authority.

13

Road Traffic Authority of Korea (2025), Traffic Accident Analysis System (TAAS). Available at: https://taas.koroad.or.kr (Accessed: 1 May 2025).

14

Seoul Metropolitan Government (2025), Internal Administrative Data on Voluntary Driver's License Surrender (운전면허 자진반납 내부 행정자료), Seoul: Seoul Metropolitan Government.

15

Statistics Korea (2024), Population Projections for Provinces: 2022-2052 (장래인구추계 시도편), Daejeon: Statistics Korea.

16

UK Parliament, House of Commons Library (2025), Driving Licences for the Over-70s. Available at: https:// commonslibrary.parliament.uk/driving-licences-for-the-over-70s/ (Accessed: 20 February 2025).

Information
  • Publisher :Korean Society of Transportation
  • Publisher(Ko) :대한교통학회
  • Journal Title :Journal of Korean Society of Transportation
  • Journal Title(Ko) :대한교통학회지
  • Volume : 44
  • No :4
  • Pages :497-510
  • Received Date : 2026-01-06
  • Revised Date : 2026-02-04
  • Accepted Date : 2026-04-29
  • DOI :https://doi.org/10.7470/jkst.2026.44.4.497
Journal Informaiton Journal of Korean Society of Transportation Journal of Korean Society of Transportation
Archives
: 2015 Vol.34~
  • scopus
  • NRF
  • KOFST
  • crossref cited-by
  • crosscheck
  • orcid
  • open access
  • ccl
Journal Informaiton Journal Informaiton - close