The principal purposes of this introductory paper are to identify and describe the main aspects of marine traffic engineering, and to suggest ways in which traffic engineering principles and methods developed for land and air transport systems may be applied to marine problems. Traffic engineering is a relatively new branch of engineering science, but it was quickly and widely recognized as essential in ensuring that all forms of land and air transport operate safely and efficiently. However, although sea transport is a long established activity, it is only during the past few years that marine traffic engineering has begun to emerge as a separate aspect of this broader scientific discipline.