TRANSPORTATION IN THE UNITED STATES is essential to the physical and economic well-being of the country. In general, the transportation infrastructure in the United States has stood up well, leading to a false sense of security and to our taking it for granted. We are currently faced with the need to maintain, repair, and reconstruct the existing systems to extend their life expectancies, or to develop new technologies to replace them with more efficient and effective systems. To understand these challenges, an overview of the current material and testing procedures has been prepared.