Elsevier has published the International Encyclopedia of Transportation on May 2021. Containing almost 600 articles, the Encyclopedia brings a cross-cutting and integrated approach to all aspects of transportation from a variety of interdisciplinary fields including engineering, operations research, economics, geography and sociology in order to understand the changes taking place. Emphasising the interaction between these different aspects of research, it offers new solutions to modern-day problems related to transportation. NTUA Associate Professor George Yannis and Assistant Professor Eleonora Papadimitriou actively contributed with the following chapter: