Effects of Offset and Angled Impact Conditions on Occupant Risk Index and Lateral Vehicle Behavior in Truck-Mounted Attenuators

A truck-mounted attenuator (TMA) is a roadside safety device designed to protect road workers and occupants of colliding vehicles. In countries such as those in Europe and the United States, full-scale crash tests of TMAs have been conducted under various conditions, including head-on, offset, and angled impacts. By contrast, only head-on crash tests have been performed in Korea after it introduced TMA test standards in 2014. In this study, occupant risk indices and post-impact vehicle behavior were analyzed under offset and angled impact conditions via numerical simulations and full-scale crash tests. The results indicate that the occupant risk indices decreased under the offset and angled impact conditions, while significant lateral vehicle motion occurred. This behavior may increase the likelihood of secondary collisions with adjacent traffic in real-world crash scenarios. Therefore, offset and angled impacts, which have been considered optional conditions, should be included as mandatory test items in TMA performance evaluations. In addition, further analyses and the establishment of safety measures addressing vehicle lateral behavior are required.