This document proposes to establish an internationally harmonized methodology for assessing greenhouse gas emissions covering four life cycle stages: material production, parts production and vehicle assembly, use phase, and end-of-life treatment. The methodology employs a four-level framework corresponding to different data availability and analytical complexity, from generic research-level assessments to detailed company-specific reporting. It specifies requirements for data collection, energy modeling, allocation procedures, and recycling calculations, using metrics based on IPCC standards. The resolution document would provide non-binding guidance for manufacturers, suppliers, and authorities conducting vehicle carbon footprint studies.