boundary completeness. One such database is the Environmental Performance in Construction (EPiC) Database developed at The University of Melbourne, which includes embodied energy data for over 250 mainly construction materials. This database also includes values for embodied water and greenhouse gas emissions. The main reason for differences in embodied energy data between databases is due to the source of data and methodology used in their compilation. Bottom-up 'process' data is typically sourced from product manufacturers and suppliers. While this data is generally more reliable and specific to particular products, the methodology used to collect process data typically results in much of the embodied energy of a product being excluded, mainly due to the time, costs and complexity of data collection. Top-down environmentally-extended input-output (EEIO) data, based on national statistics can be used to fill these data gaps. While EEIO analysis of products can be useful on its own for initial scoping of embodied energy, it is generally much less reliable than process data and rarely relevant for a specific product or material. Hence, hybrid methods for quantifying embodied energy have been developed, using available process data and filling any data gaps with EEIO data. Databases that rely on this hybrid approach, such as The University of Melbourne's EPiC Database, provide a more comprehensive assessment of the embodied energy of products and materials. In common materials Selected data from the Inventory of Carbon and Energy ('ICE') prepared by the University of Bath (UK) In transportation Theoretically, embodied energy stands for the energy used to extract materials from mines, to manufacture vehicles, assemble, transport, maintain, transform them and to transport energy, and ultimately to recycle these vehicles. Besides, the energy needed to build and maintain transport networks, whether road or rail, should be taken into account as well. The process to be implemented is so complex that no one dares to put forward a figure. According to the :fr:Institut du développement durable et des relations internationales, in the field of transportation, "it is striking to note that we consume more embodied energy in our transportation expenditures than direct energy [...]. Put in other words, we consume less energy to move around in our personal vehicles than we consume the energy we need to produce, sell and transport the cars, trains or buses we use ". Jean-Marc Jancovici advocates a carbon footprint analysis of any transportation infrastructure project, prior to its construction. In