The aim of this work is to analyze the use of hybrid powertrains in public transport by heavy vehicles. In the last years, the increasing demand for sustainable mobility has stimulated the use of electrified powertrains also in the heavy-duty transport sector. Numerous European regulations prohibit non-electrified vehicles from entering historical centers, in highly congested urban areas and airports. The use of an electric motor coupled to an Internal Combustion Engine (ICE) in a bus, whose motion is characterized by continuous transients, especially in the case of vehicles dedicated to urban transport where the distance between two successive stops is reduced. In the work, it was decided to investigate the various hybrid architectures normally used in vehicles and put on a multibody model to test optimal management systems of the engines present on the vehicle.