Intelligent transportation systems (ITSs) can operate successfully only if selection and training of personnel are carried out in a systematic, theoretically sound way. Given the increasing responsibility of operators, a scientific analysis to develop requirements and specifications for training and selection is necessary. Despite the increasing deployment of ITS in industrialized countries, no systematic, empirically supported requirements analysis-including ability level, as well as task level-has yet been done for traffic operators in traffic management centers (TMCs), tunnel operation centers (TOCs), and urban traffic control centers (UTCs). A general requirement profile was established-including knowledge, skills, and abilities-for operators in all three different center types. Differences for traffic operations in TMCs, TOCs, and UTCs were highlighted. Moreover, consequences were drawn for selection processes for potential operations employees and, an overview was provided of tasks needing to be taught specifically. The methods and results shown are particularly helpful for researchers and practitioners in the operational field of ITS.