Continued advances in onboard computing technology are allowing automotive companies to accelerate the level of functionality delivered on new vehicles through electronics and software. New features such as hybrid powertrains and vehicle stability control are driving the need for vehicle-level supervisory control. In this work, the supervisory controller was defined in a modular and hierarchical structure in order to achieve better reusability and flexibility in incorporating new technologies into existing applications. In addition, a database tool was developed for the purpose of managing the complexity associated with maintaining the modular and hierarchical structure. Finally, the application of this work to advanced development of new hybrid vehicle prototypes is described.