On September 15, 2001, a four-barge tow struck and collapsed Bent 32 of the Queen Isabella Causeway Bridge (Park Road 100 bridge crossing the Gulf Intracoastal Waterway) in Texas. In the aftermath of the collapse, the Bridge Division of the Texas Department of Transportation conducted a vessel impact risk analysis for all bridges crossing waterways with documented barge or cargo vessel traffic. To identify all bridge crossings over navigable waterways, Bridge Division engineers queried the Bridge Inspection Database and confirmed the resulting list with district personnel. Investigating engineers screened the bridges in steps on the basis of exposure of structural elements to vessel traffic, bridge type, and level of protective system already in place. They then evaluated bridges requiring analysis in accordance with the load and resistance factor design (LRFD) vessel collision provisions of the AASHTO" LRFD Bridge Design Specifications." The engineers then scored bridges on the basis of vulnerability to vessel impact and criticality of bridge structure and normalized the scores to assign a value of 100 to the bridge representing the worst combination of these criteria. Investigators identified five bridges that required modification or installation of protective systems. From their findings, a program was initiated to design and install protective measures at each of the five bridge locations. In June 2003 a contract was assigned for the first project, to install protective measures on the south vessel approach of the Queen Isabella Causeway Bridge. In February 2004, a second project was begun, to install similar protective measures on the north vessel approach of the same bridge. Design is proceeding on protective measures for the other four bridges.