PURPOSE In navigable waterway areas@ where vessel collision by merchant ships and barges may be anticipated@ bridge structures shall be designed to prevent collapse of the superstructure by considering the size and type of the vessel@ available water depth@ vessel speed@ and structure response. The requirements apply to all bridge types which cross a navigable shallow draft inland waterway or canal with barge traffic@ and deep draft waterways with large merchant ships. The provisions are for normal merchant steel-hulled vessels (ships and barges) and are not applicable for waterways whose maritime traffic consists of recreational or other special vessels constructed of wood or fiberglass. The intent of the vessel collision requirements is to establish analysis and design provisions to minimize bridge susceptibility to catastrophic collapse. The purpose of the provisions is to provide predictable design vessel collision effects in order to proportion bridge components with a reasonable resistance to collapse. The provisions apply to bridges crossing navigable waterways which carry waterborne commerce as established by federal and state agencies. Judgment should be used when applying the criteria to waterways in which no defined navigation channel exists and no commercial maritime traffic can be reasonably anticipated. Bridges over a navigable waterway meeting the criteria above@ whether existing or under design@ should be evaluated as to vulnerability to vessel collision in order to determine prudent protective measures. The recommendations listed below summarize the essential elements which should be addressed in developing a program for evaluating bridges and providing pier protection for vessel collision.