Improving the safety and efficiency of transportation systems remains a global priority—both from an engineering and health perspective

Roadways classified as state routes in both rural and urban settings are tree-lined, creating a canopy over the pavement surface. Although trees are beneficial to the environment, they pose a hazard to road safety in a variety of ways. For example, they offer reduced skid resistance due to fallen leaves; restrict direct sunlight on pavement surface, causing the formation of black ice and fog; and increase the risk of entire trees/branches/fruits falling on passing vehicles or blocking traffic lanes. State agencies have undertaken the task of eliminating tree canopies, inviting widespread criticism. Currently, there is a gap in the literature about the impact of tree canopy on traffic safety in the form of scientific research. This paper addresses this gap by presenting insight into the benefits of tree-trimming and/or removal operations along state routes in Ohio. Adopting the Empirical Bayesian approach, this study evaluates crashes to quantify the safety benefits. Additionally, a surrogate safety assessment was conducted to evaluate driver behaviors in the presence/absence of tree canopy. The results indicated that roadside tree trimming and pruning showed site-specific safety benefits at most locations, though no consistent project-level crash reduction or conclusive effects on surrogate safety measures, such as reduced speeds and hard braking, were observed.

Road traffic injuries remain a leading cause of preventable death and disability worldwide, with disproportionate impacts on vulnerable and underserved populations. While transportation safety efforts have traditionally focused on engineering countermeasures and behavioral modification, persistent inequities in crash risk and injury outcomes indicate the need for a broader systems-based approach. This discursive paper applies the National Institute on Minority Health and Health Disparities (NIMHD) Research Framework to conceptualize road traffic safety across multiple domains, i.e., biological, behavioral, physical/built environment, sociocultural environment, and health care system, and levels of influence including individual, interpersonal, community, and societal factors. By integrating transportation engineering strategies such as Safe System design, roadway countermeasures, and vehicle technologies with public health perspectives on injury prevention and health equity, the paper illustrates how structural conditions shape crash occurrence, injury severity, and post-crash outcomes. The proposed multilevel and multisectoral framework emphasizes cross-sector collaboration among engineers, public health professionals, policymakers, and community stakeholders to reduce preventable injury and advance equity. This integrated model offers a conceptual foundation for future empirical research, policy development, and implementation strategies aimed at achieving population-level improvements in road safety.

Road traffic injuries remain a leading cause of preventable death and disability worldwide, with disproportionate impacts on vulnerable and underserved populations. While transportation safety efforts have traditionally focused on engineering countermeasures and behavioral modification, persistent inequities in crash risk and injury outcomes indicate the need for a broader systems-based approach. This discursive paper applies the National Institute on Minority Health and Health Disparities (NIMHD) Research Framework to conceptualize road traffic safety across multiple domains, i.e., biological, behavioral, physical/built environment, sociocultural environment, and health care system, and levels of influence including individual, interpersonal, community, and societal factors. By integrating transportation engineering strategies such as Safe System design, roadway countermeasures, and vehicle technologies with public health perspectives on injury prevention and health equity, the paper illustrates how structural conditions shape crash occurrence, injury severity, and post-crash outcomes. The proposed multilevel and multisectoral framework emphasizes cross-sector collaboration among engineers, public health professionals, policymakers, and community stakeholders to reduce preventable injury and advance equity. This integrated model offers a conceptual foundation for future empirical research, policy development, and implementation strategies aimed at achieving population-level improvements in road safety.