The goal of this research was to obtain insight in how engineers deal with ethical issues in daily engineering design practice. It was reasonable to assume that ethical issues and the way engineers deal with them depend on characteristics of the design process. Vincentiï¿½s dimensions were used to characterize different design processes: design type and design hierarchy. In normal design the working principle, how the product works, and the normal configuration, the shape and parts of the product, are known. To obtain empirical data, case studies have been conducted. Two radical design processes, one high level conceptual design (an ultralightweight sustainable car) and one lower level design (a lightweight trailer) have been studied. Besides these two radical design processes, two normal design processes also differing in design hierarchy have been studied (design of piping and equipment for the (petro)chemical industry and the design of a bridge).
In the radical design processes ethical questions are especially related to operationalisations of ethical criteria such as safety and sustainability and trade-offs between design criteria. These operationalisations and trade-offs are made using internal design team norms. These internal norms are based upon design experience, personal experience and education of the design team members. In the normal design processes a regulative framework is used. A regulative framework consists of European and national regulation, codes and standards, and interpretations of regulation and code given by certifying organisations. The regulative framework provides operationalisations and some guidelines for trade-offs. This does not mean that all ethical issues can be dealt with by referring to the regulative framework. Some decisions that engineers make for example concerning safety are not covered by the regulative framework. Parts of the regulative framework are inconsistent and ambiguous. Another important ethical issue is that it is not clear whether the regulative framework is accepted by all affected actors. The descriptions of the design processes were used to formulate ideas on the conditions for warranted trust in engineers making normal and radical designs.