This study tries to resolve the questions of what methods are appropriate in evaluating and quantifying proposed engineering structures in the initial design phase. The objective was to create a set of criteria to focus on such important issues as environment and social acceptance in addition to technical and economical aspects. These methods are to provide a statistical sample and therefore a larger and more objective information to the decision making body at the time of selecting a final design. During the realization of this work a total of 160 people where interviewed and their opinions compared and evaluated. To obtain a broad spectrum of opinions, experimental groups made up of an equal number of engineers, architects, environmental experts and non professionals were selected to choose among 14 possible design alternatives for a freeway overpass. The proposed design variants were presented to them as a 3_D computer generated model. The first task was to select similar designs based upon a common attribute. Then, the groups were asked to rate the designs on a scale from 0 to 10 based on preference, impression, typicality and costs. The two tasks proved to be useful in allowing a statistical evaluation of the results and a qualitative interpretation of engineering structures. Application of this approach is promising in such areas as the realisation of public work projects or any other engineering conceptual design. An additional study deals with the influence of the visualisation medium (2D_drawings, 3D_drawings, video).