The Automatic Identification System: Then, Now, and in the Future

After the Exxon Valdez oil spill in 1989, Congress enacted the Oil Pollution Act of 1990, which changed how we deal with oil pollution prevention and response and made participation in Coast Guard vessel traffic services VTS mandatory. One other important provision in the law was the mandate to create a dependent surveillance system to monitor tankers navigating to and from Valdez, Alaska. Room for Improvement Prior to this incident, vessel traffic services typically provided vessel information by inquiring about vessels intentions and tracking their movement within the system via some manual plotting board or similar device. Though the inclusion of radar greatly enhanced the ability to track and monitor vessel movements, its range is limited, so the cost of providing full radar coverage throughout an entire VTS area and its approaches was prohibitive. Further, radar does not provide the ability to positively identify a vessel among other vessels or physical objects, such as ice. This limitation was always known, but became more evident after the Exxon Valdez disaster.