Involving landscape architecture inside the transport sector in France has been firmly established at the end of the XXth century. This was mainly supported by a current of thought being environmental friendly and aware of the importance of sustainable development. The place of a landscape architect has thus improved progressively. Nowadays the construction of an interurban road cannot go without the assessment of the environmental impacts. The assessment is directly implemented in the planning process, whithin the impact inspection, making it necessary to point out the environmental method used. Apart from that, there is no method suggested, neither in the jurisdiction nor in guides. You can observe a certain absence of rigor as well as superficiality in the methods precisions. The goal of this dissertation is to set the basics of a method improving the aspects of the landscape impacts. We will be inspired by Canadian ways of approach, more precisely from the work of Hydro-Quebec (1993) and by the theoretical work of Leduc & Raymond (2000) setting up a more rigorous method. The limits of this method as well as ways to be improved are presented in the end of this dissertation in order to open up a discussion and invite to continue the research on this subject.