Impact absorbing pavement provides head protection comparable to helmets in oblique impacts

Head injuries constitute an increasing public health concern. Although motor vehicle injuries have steadily declined in Sweden, the number of injuries and fatalities among unprotected vulnerable road users (VRUs) continues to rise. Inspired by playground surfaces, rubberized asphalts have recently been developed as impact-absorbing pavement (IAP), with the dual objectives of enhancing collective safety and minimizing injuries, while promoting higher-value applications within the waste hierarchy. This study aims to biomechanically evaluate IAP's head injury protection performance by conducting laboratory oblique impact tests to obtain impact kinematics and finite element (FE) simulations to estimate brain strain responses. A total of 30 impact tests were performed on five kinds of asphalt samples under three impact locations. Eleven kinematics-based and five strain-based head injury metrics were analyzed and compared. For example, the peak linear acceleration (PLA), peak angular velocity (PAV), and max principal strain (MPS) were lower than 150 g, 36 rad/s, and 0.4 during oblique impact against the IAP prototype. The results demonstrated that the IAP achieved a comparable head protection performance to helmets, indicated by both the linear-based and rotational-based head injury metrics at 6 m/s. These findings show that IAP has significant potential to reduce head injuries among unprotected VRUs and contribute to a safer traffic environment.