The fourth Structural Materials Technology NDT Conference was held in Atlantic City, New Jersey, with over sixty speakers presenting on a wide variety of topics. The goal of this conference was to inform engineers and researchers of the new nondestructive testing/nondestructive evaluation (NDT/NDE) technologies and techniques available for use in transportation construction. The use of alternative materials is challenging NDT/NDE professionals to develop new methods or modify existing techniques to address quality control, quality assurance, and long-term monitoring of structures built or strengthened with these materials. One such alternative is fiber-reinforced polymer (FRP) products. This conference included papers on this topic and a panel discussion that focused on the future of NDT/NDE technologies for structures built or rehabilitated with FRP composites. These proceedings contain the 62 papers that were presented at the conference, arranged according to session number. An author index is included.