The desired behaviour of a road safety barrier is to protect occupants by means of constraining and redirecting errant vehicles away from a hazardous area. The W-beam guardrail system anchored in roadside gravel is common in Sweden. Although this type of safety barrier has been approved in the European standard full-scale crash tests, efforts are still required to investigate the protection performance in the real world impact conditions. Using a computer model of W-beam guardrail, a parameter study was designed with the aim to identify the most critical condition from the representative vehicle impact conditions through the investigation of the performance of the guardrail. The study investigated the representative impact conditions in terms of two parameters, i.e. an angle of 10-25 degrees and an initial contact position between two adjacent posts. The ranges of the parameters were identified by means of accidents analysis and the review of crash test criteria. In the simulations through the finite element analysis software LS-DYNA, the combination of the maximum impact angle 25 degrees and an impact position at the midpoint of a span were found to be the most critical impact condition. In contrast, the critical position is often set to be at a post in the standard tests. The numerical analysis identified a potential critical impact point that needs to be considered for full-scale crash tests (A). For the covering abstract of the conference see ITRD E212343.
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