New Product and Process Development (NPPD) in the automotive industry, integrated in large projects, focuses on producing vehicles while optimising performance (costs, quality, safety) and considerably reducing the " time to market ". The first phase in NPPD is what we will call the " Project definition " phase. This phase is decisive because the project outcomes depend upon the success of this phase, i.e. capability to define ambitious and feasible objectives corresponding to the market. This phase is a collaborative decision-making phase. The two main research questions are: how to support collaborative decision-making in the early stages of NPPD, and what an adapted project management approach for these phases is. Research methodology used in this study is case-based using semi-structured interviews and participation/observation of working groups. The case study concerns 7 managers or engineers working in this phase and 9 vehicle development projects. The findings of this research point out the need for a new management paradigm and a proposition of a project management framework for the early stages of NPPD.