  Ontology is the explicit and formal representation of the concepts in a
domain and relations among them. Transportation science is a wide domain
dealing with mobility over various complex and interconnected transportation
systems, such as land, aviation, and maritime transport, and can take
considerable advantage from ontology development. While several studies can be
found in the recent literature, there exists a large potential to improve and
develop a comprehensive smart mobility ontology. The current chapter aims to
present different aspects of ontology development in general, such as ontology
development methods, languages, tools, and software. Subsequently, it presents
the currently available mobility-related ontologies developed across different
domains, such as transportation, smart cities, goods mobility, sensors. Current
gaps in the available ontologies are identified, and future directions
regarding ontology development are proposed that can incorporate the
forthcoming autonomous and connected vehicles, mobility as a service (MaaS),
and other disruptive transportation technologies and services.
