The design process can be considered as series of decisions supported by modeling and simulation (M&S). Current developments aim at supporting this decision making with regard to increasing resources committed in the M&S process. To understand possible decision support, we conducted an empirical study in a car manufacturing company to map out the decision-making process during the development phase. A qualitative data analysis was performed to understand the difficulties and the needs expressed by decision makers. Industrial preliminary observations have shown that decisions regarding design issues are often postponed, causing iterations, and time and cost overruns in the development process. The study revealed that decisions are escalated to upper hierarchical levels as complexity and uncertainty increase and as the tradeoffs become impactful. A lack of knowledge about the M&S performance and limits, a lack of clarity due to design ambiguity, and uncertainty are more likely to cause iterations and delay. In addition, decision makers and stakeholders are sometimes unadvised of the influence of the decision under consideration on subsequent decisions and on the profit. These findings are interesting as they shed light in terms of decision supported needed in the future.