In this paper, we deal with modeling consensus formation process in a road construction project between two conflicting groups such as regional inhabitant and road enterpriser. For this purpose, we tried to evaluate the effectiveness of various countermeasures for preventing the environmental impact of heavy road traffic. The disutility functions are constructed from the questionnaires to the environmental specialists to evaluate the effect of constructing a noise barrier taking into account the trade-off relation between the obstruction of landscape and the prevention of environmental impact. The disutility function of the road enterpriser is measured as the difficulties of realizing the countermeasures based on the costs. We construct the group disutility functions for two conflicting groups from the questionnaires to the environmental specialists. The group disutility theory based on convex dependence is applied to express the mutual concessions between two conflicting groups in the model. The group disutilities are evaluated for various countermeasures using the group disutility functions developed in this paper.