Disaggregating safety impact of voluntary older driver's license surrender: A crash-type-specific analysis

South Korea's rapidly aging population has raised growing concerns over traffic safety, particularly regarding crashes involving older drivers. In response, the government introduced a voluntary driver's license surrender program in 2019 aimed at mitigating crash risk among older drivers. This study evaluates the program's impact on crashes caused by older drivers, with a focus on crash types (single-vehicle, pedestrian-involved, vehicle-to-vehicle), regional variation and changes in vehicle kilometers traveled. While total crash reductions were not statistically significant, the program yielded meaningful and persistent effects for specific crash types. Single-vehicle crashes—which are closely linked to autonomy-related impairments—declined by 18.8 % overall and by 33.8 % in rural areas. Pedestrian-involved crashes dropped by 19.6 % in urban areas but showed no significant change in rural regions. In contrast, vehicle-to-vehicle crashes were not significantly affected. In addition, the program led to a statistically significant 8.6 % reduction in daily driving distance among older drivers, supporting its behavioral impact. These findings highlight the importance of targeting surrender programs toward high-risk groups and geographic areas. To maximize long-term effectiveness, such programs should be complemented by regionally tailored mobility infrastructure, enhanced public transport options, and broader road safety interventions.