PIANC Panama - Agenda

Methods of quantitative risk assessment are needed to evaluate and compare navigation risks in coastal ports so that port managers can determine where risks are high and take actions to mitigate those risks where appropriate. This presentation describes how data contained in automatic identification system (AIS) messages can be used to assess collision and grounding risks in coastal ports. Commercial vessels and many recreational vessels are equipped with AIS transmitters, which broadcast information on that vessel’s identity, location, course and speed at intervals of two to 30 seconds. In the United States (US), the US Coast Guard harvests and archives these messages for the purpose of maritime domain awareness, which is defined as the effective understanding of anything within the maritime domain that affects security, safety, economy, and environment. Collision risks are analyzed using the concept of a ship domain, which is the area around each vessel that should remain clear of other vessels. The ship domains used in this study are elliptical and have dimensions that vary with the swept path of each vessel. The metric of collision risk in navigation channels is the fraction of AIS position reports, normalized to control for differences in transmission frequency, which satisfy several criteria for a ship domain violation. The metric, which can be interpreted as the probability of a ship domain violation given that at least one vessel is present, can be calculated for individual channels, groups of channels, or entire ports and provides the basis for quantitative comparisons of collision risk across navigation channels and coastal ports. These metrics of risk provide an objective basis for relative comparisons of risk in different ports and waterways.