Systematic review of life cycle assessments on carbon emissions in the transportation system

The transportation sector significantly contributes to carbon emissions, prompting a surge in research on emission reduction. Carbon estimation methods include bottom-up, top-down, and life cycle assessment (LCA). Unlike the first two, LCA offers a holistic view of emissions throughout the entire transportation system, facilitating precise reduction strategies. This study examines LCA research on transport carbon emissions, revealing scope, impact factors, and policy assessments in 243 selected articles. The primary focus is on road transport and vehicles, with fuel well-to-wheel and vehicle LCAs comprising 32.9% of analyses. While emerging technologies like electric vehicles show direct emission advantages, a life cycle perspective is crucial for accurate assessment. Policy evaluations centers on banning fossil fuel vehicle and promoting zero-emission vehicles. Coordinated policies are essential, as isolated ones may not achieve emission reduction goals, and comprehensive policies must balance stakeholder interests. Future carbon reduction LCA should considering technological innovations, mode optimization, and regional disparities.