Scheduling transit vessels in the Istanbul Strait

Due to its geographical features and unique location, the Istanbul Strait is one of the most significant and critical waterways in the world. Geographical features, meteorological conditions, local maritime traffic, the density of maritime traffic and cargo characteristics make transit vessel navigation difficult in the Istanbul Strait in each passing day. For safe vessel navigation, the Istanbul Strait Vessel Traffic Control Authority (VTCA) has defined some rules and regulations, which can change according to vessel class and meteorological conditions. The objective of this study is to develop and implement an optimization model to schedule the entrances to the Istanbul Strait of the arrived (and waiting) transit vessels, while minimizing and balancing the waiting times of vessel classes against the vessel density and separation (between two consecutive transit vessels) and traffic flow direction requirements in the Istanbul Strait. One of the most significant policies of the VTCA is the minimum pursuit distance between vessels, which differs from one vessel type to another. Minimum pursuit distance rule can be changed by the VTCA based on meteorological conditions or maritime traffic density. Other significant policies of the VTCA are unidirectional traffic flow for transit vessels and not giving permission to some vessel classes to enter the Strait in day time or night time. However, passing through the Strait in bidirectional flow in favorable meteorological conditions is admitted for some vessels. In this study, a mixed integer zero-one formulation is developed and solved for the above defined scheduling problem. In addition to the current situation, parameters such as minimum pursuit distances, number of available pilots and arrival pattern of vessels in the Istanbul Strait are changed for scenario analysis and the effect of change in parameters on performance measures are investigated.