Elderly pedestrian safety in silver zones: A temporal instability analysis of injury severity determinants

Elderly pedestrians are particularly vulnerable on the road, facing disproportionately higher fatality rates in traffic crashes compared to younger individuals. Countries like South Korea have responded by designating "silver zones" with traffic-calming measures in places frequented by many elderly pedestrians. Nonetheless, the fatal/severe injury (FSI) crash rates among elderly pedestrians in these zones remain alarming. This study assesses the contributory factors influencing silver zone-related elderly pedestrian injury severity outcomes and examines the consistency of their impact throughout time. The study employed a random parameters logit model with heterogeneity in the means approach to investigate crashes involving elderly pedestrians in silver zones in South Korea at different stages of the pandemic: before, during, and after the COVID-19 pandemic in 2018–2019, 2020, and 2021–2022, respectively. Initial results, as indicated by likelihood ratio tests, indicate that the variables influencing elderly pedestrian injuries throughout various pandemic phases in silver zones exhibit notable temporal instability. Factors increasing the probability of FSI outcomes include crashes occurring between 4-7AM, drivers failing to yield, traffic signal violations, spring season, head impacts, and Friday crashes. Some factors showed varying impacts across different pandemic stages. During and after the onset of the pandemic, there was a more pronounced increase in the FSI outcome likelihood among elderly pedestrians involved in crashes at pedestrian crossings and those experiencing chest impacts compared to the period pre-pandemic. Conversely, crashes involving drivers between the ages of 40-44 and those resulting in waist impacts during and post-pandemic had a lower chance of FSI crash outcomes, following an initial increase pre-pandemic. The insights from this study provide policymakers with a clearer knowledge of how factor impacts have changed over recent years. This information can be used to refine current road safety policies and improve the safety of elderly pedestrians in silver zones.