The goal of this study is to examine the data and assumptions used in the report entitled “Reduction and Testing of Greenhouse Gas (GHG) Emissions from Heavy Duty Vehicles – Lot 1: Strategy,” which was prepared for the European Commission by AEA-Ricardo to derive conclusions regarding the GHG reduction potential of heavy-duty vehicles (HDVs) in the European Union (EU). This analysis is based on a comparison between HDV technologies offered in the United States and those offered in the EU. Many of the vehicle and engine manufacturers that sell products in the United States are EU-based, and thus technologies are expected to be similar.