To improve the protective capabilities of existing low-grade concrete guardrails against heavy vehicles,three types of composite protective plates designed for direct installation on the surface of concrete guardrails were developed. Refined finite element (FE) models of truck-guardrails were established, and the reliability of these models was verified by comparison with crash test results. Six evaluation indexes, including impact force,collision angle variations,vehicle trajectory, height variations of the carriage box tail,vehicle dynamic extroversion value and camber angle, were considered. The anti-collision performance of the three schemes was compared and analyzed. The results indicate that all three kinds of guardrails effectively guide vehicles to turn smoothly during the integral truck impacts. Scheme 1, without hindrance, demonstrates superior performance in key indices compared to the others. Under towed truck impacts, scheme 1 exhibits excellent guiding and blocking capabilities, with an exit angle of only 0.75°.The protection energy of the combined guardrail reaches 650 kJ,providing a protection capacity 4 times greater than the existing low-grade guardrail.