The United States possesses an effective and efficient surface transportation infrastructure that promotes both the well-being of its citizens as well as important economic and national security goals. The level of security afforded this infrastructure is relatively low compared to the security enhancements recently implemented in the commercial aviation sector. However, there is sufficient reason to believe that the security levels of the surface transportation modes need to be raised as the threat level increases and the vulnerabilities of the current infrastructure become apparent. There are potential threat scenarios where a significant loss of human life or a major disruption to a key segment of the nation's transportation infrastructure could occur. Given this fact, it is essential that well-planned, coordinated actions be taken to reduce the possibility that such events occur. Such actions should represent a coordinated approach by a partnership of public and private sector institutions to: identify vulnerabilities and threats; and enhance the security of key surface transportation infrastructure segments and operations.