Developed at Argonne National Laboratory, the Powertrain System Analysis Toolkit (PSAT) is a state-of-the-art flexible and reusable simulation package used to facilitate advanced vehicle (i.e., hybrid, hydrogen, and fuel cell) development. PSAT was designed to serve as a single tool that can meet the requirements of automotive engi-neering throughout the development process—from modeling to control.PSAT allows users to accurately model advanced vehicle components, their control strategies, and component interactions in a systems context, thereby enabling users to conduct detailed labo-ratory benchmark testing of advanced compo-nents as they are being developed. PSAT provides accurate performance and fuel economy simula-tions, permitting automotive and truck manu-facturers and their suppliers to quickly select the advanced technologies that will best meet their needs, and helping them bring their advanced vehicles to market as quickly and cost effectively as possible. Thus far, PSAT has been transferred, through licensing agreements, to more than 200 users worldwide. Among licensed PSAT users are major automakers—including General Motors, Ford, DaimlerChrysler, and Hyundai—automo-tive suppliers, energy companies, research insti-tutions, and universities.