TRB's National Cooperative Highway Research Program (NCHRP) Report 525, Vol. 16: A Guide to Emergency Response Planning at State Transportation Agencies is designed to help executive management and emergency response planners at state transportation agencies as they and their local and regional counterparts assess their respective emergency response plans and identify areas needing improvement. NCHRP replaces a 2002 document, A Guide to Updating Highway Emergency Response Plans for Terrorist Incidents. NCHRP Report 525, Vol. 16 is supported by the following online appendixes: Appendix K - Annotated Bibliography; Appendix L - White Paper on Emergency Response Functions and Spreadsheet Tool for Emergency Response Functions; Appendix M - 2010 Guide Presentation. NCHRP Report 525: Surface Transportation Security is a series in which relevant information is assembled into single, concise volumes - each pertaining to a specific security problem and closely related issues. The volumes focus on the concerns that transportation agencies are addressing when developing programs in response to the terrorist attacks of September 11, 2001, and the anthrax attacks that followed. Future volumes of the report will be issued as they are completed.