<p>Topology optimization density contour data.</p>

Vehicle lateral intrusion is substantially reduced: under the 55 t tractor-semitrailer collision condition, the maximum dynamic equivalent vehicle lateral intrusion value (VIn) is reduced by 64.2% compared with conventional guardrails. In terms of lightweight design, the weight per linear meter of the guardrail is decreased from 230 kg to 180 kg, representing a reduction of 21.7%. Economic analysis shows that the reduction in material consumption lowers the overall material cost by approximately 10%–15%.

This study demonstrates a material-structure co-design method that simultaneously improves safety, lateral intrusion resistance, lightweight level and economy for HA-level heavy-vehicle conditions, providing a theoretical basis and technical support for the engineering application of a new generation of high-performance bridge guardrails.</p></div>