Geographic Information Systems for Estimating Coastal Maritime Risk

The U.S. Maritime Administration made a strong commitment to short-sea shipping in 2010 in America's Marine Highway Program. There are few statistics about coastal vessel traffic, however, and even less is known about casualty rates in those waters because of the absence of trip data and the relatively poor quality of casualty data. Geographic information systems (GIS) are unique tools that enable greater visualization and understanding of complex problems. A methodology was used to adapt a GIS-based highway planning traffic assignment model for use in maritime risk assessment. The planning model routed 12 years of vessel entrance and clearance data through an international waterway network to estimate the number of trips traversing network links by any number of metrics, including year, ship type, flag of registry, and draft. The risk methodology deployed a 100-mi² mesh (10 mi × 10 mi) over the entire United States and coastal waters to estimate the highest casualty rate (casualties per million vessel trips) and casualty frequency locations.