This JRC Technical Report provides an introduction to the JRC system dynamics based Powertrain Technology Transition Market Agent Model (PTTMAM). This comprehensive system dynamics model, covering the period 1995 to 2050, was designed to capture the key feedbacks and interactions between manufacturers, authorities, infrastructure providers and users across the 28 EU member states and 16 powertrain options available in the light duty vehicle market. The purpose of this report is to serve as a source of reference for future publications based on the PTTMAM and for those engaged in the interpretation of PTTMAM output. In addition to describing the general PTTMAM structure and main interactions, this report sets out a baseline scenario to demonstrate the flexibility of the model. Only brief mention is made to model validation, in order to assure the robustness to the reader, with more detail provided as Annexes to the report. Due to the high degree of complexity within the model the report remains a high level overview and should the reader be interested in learning more detail on the structure, development or specific parameters they should refer to the authors directly. We welcome any suggestions for adaption or improvement.