This study aimed to analyze the impact of implementing a voluntary driver's license return program on reducing traffic crashes for older drivers who were previously involved in traffic accidents. The traffic crashes caused by elderly drivers were categorized by crash type. We used the Chi-square test to compare municipalities that implemented the program in 2019 and 2020 with those that did not and explored variations in crash types based on the residential areas and age groups of elderly drivers. The voluntary driver's license return program reduced considerably the number of single-vehicle crashes involving elderly drivers. Moreover, while all crash types decreased in rural areas, only pedestrian–vehicle, and single-vehicle crashes were reduced considerably in urban areas. In terms of age groups, drivers aged >75 years were associated with reduced numbers of crashes (all types). Similarly, the 70–74 age group demonstrated considerable reductions in pedestrian–vehicle and single–vehicle crashes, emphasizing the importance of encouraging and supporting license returns among these age groups. First, because the characteristics of each crash type vary, it is important to analyze the impact of voluntary driver’s license returns on crash reduction, with a focus on specific crash types. Second, voluntary license returns should be promoted in all regions. However, in rural areas with limited access to public transportation, mobility must be supported by the introduction of DRT. Third, given that drivers aged >75 years were associated with reduced numbers of crashes (for all types of crashes), priority policies should be implemented to encourage license returns within this age group, along with tailored incentives. However, as the voluntary license return program is intended to support selfinitiated cessation of driving without compulsion, strategies should also be explored to promote voluntary returns without age restrictions. Fourth, a standardized evaluation system should be established to enable older drivers to assess their driving abilities and physical conditions, further encouraging voluntary license returns.

PURPOSES : This study aimed to investigate the factors affecting the severity of traffic crashes caused by personal mobility (PM) devices compared with those involving victims. METHODS : Traffic crashes involving PM devices were used to build a non-parametric statistical model using a classification tree. Based on the results, the factors influencing both at-fault and victim-related crashes caused by PM devices were analyzed. The factors affecting accident severity were also compared. RESULTS : Common factors affecting the severity of traffic crashes involving both perpetrators and victims using PM devices include occurrences at intersections, crosswalks at intersections, single roads, and inside tunnels. Traffic law violations by PM device users (perpetrators) influence the severity of crashes. Meanwhile, factors such as the behavior of perpetrators using other modes of transportation, rear-end collisions, road geometry, and weather conditions affect the severity of crashes where PM device users are the victims. CONCLUSIONS : To reduce the severity of traffic crashes involving PM devices, it is essential to extend the length of physically separated shared paths for cyclists and pedestrians, actively enforce laws to prevent violations by PM device users, and provide systematic and regular educational programs to ensure safe driving practices among PM device users.