For longitudinal barriers, it is common practice to use a standard W-beam guardrail along the required highway segments and to use a stiffened time-beam guardrail in a transition region near the end of a bridge. As a result of the differences in rail geometries, a W-beam-to-thrie-beam transition element is typically used to connect and provide continuity between the two rail sections. However, the W-beam-to-thrie-beam transition element has not been evaluated according to current impact safety standards. Therefore, an approach guardrail transition system, including a W-beam-to-thrie-beam transition element, was constructed and crash tested. The transition system was attached to Missouri's thrie-beam and channel bridge railing system.