14 January 2014The purpose of this paper is to broaden the Terrestrial Transport Infrastructure (TTI) assessment process into the field of Ecosystem Services (ES), i.e., the benefits people derive from ecosystems. Taking into account ES in an ex ante assessment of public infrastructure projects is of critical importance for the improvement of transportation decision-making tools, such as Environmental Impact Assessment (EIA) and Cost–Benefit Analysis (CBA). For EIA, the integration of an ES based approach opens the possibility of measuring a loss in ES supply (and its economic value); this provides a means of selecting among different possible pathways for the infrastructure. For CBA, since the ES loss induced by the selected pathway is expressed in monetary terms, it can be integrated as a standard social cost in the analysis, permitting a more efficient control of natural capital loss. We illustrate these points by assessing the loss of a global climate regulation service due to the soil tillage and sealing caused by a TTI construction, using the example of a high-speed rail in Western France. We select three optional routes among the proposed routes and analyse which route has the least impact on the global climate regulation service and its economic value.