Buried-in-backslope (BIB) terminal designs for beam guardrails significantly reduce the risk of vehicular intrusion behind the barrier upon end-on impact by burying the end terminal in the backslope. The purpose of the study reported herein was to investigate via finite element analysis (FEA) the crashworthiness performance of the BIB terminal variations in terrain configuration according to the safety-performance evaluation guidelines included in the second edition of the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH)(1).

The BIB terminal design for 31-inch-tall guardrail systems was successfully crash tested under MASH test level 3 (TL-3) criteria by Texas A&M Transportation Institute (TTI) in a previous project (2). An FE model of the crash tested BIB terminal design was developed and validated using the Roadside Safety Verification and Validation Program (RSVVP). This model was used as the baseline model for all the design modifications considered in this project.

A survey of the Roadside Safety Pooled Fund members was conducted to gather current practices and identify common terrain configurations used for the modified BIB terminal design. Three different model configurations were selected for MASH TL-3 crashworthiness evaluation through computer simulations. All three configurations consisted of variations in foreslope ratio and width.

The selected BIB terminal design configurations were evaluated under MASH TL-3 conditions through FEA. Results from the computer simulations showed that all three configurations are likely to satisfy MASH TL-3 criteria.