Over the past couple of years, several advanced powertrain technologies, including electric vehicles (EVs), hybrid electric vehicles (HEVs), hybrid hydraulic vehicles (HHVs), and alternative-fuel vehicles, have been implemented in medium-and heavy-duty applications. In this study, several advanced powertrain configurations were selected and implemented on different vehicle applications (e.g., parcel and delivery, bus, line haul) over different time frames and were then modeled in PSAT (Powertrain Systems Analysis Toolkit), Argonne National Laboratory's vehicle modeling and simulation tool. The study was sponsored by the U.S. National Academy of Science to support the "Technologies and Approaches to Reducing the Fuel Consumption of Medium-and Heavy-Duty Vehicles" study. This paper analyses the energy balances of different applications for several vehicle speeds. Specific technologies are then selected to minimize the largest losses. Finally, their fuel consumption benefit is assessed on several drive cycles.