Transport Infrastructure, Economic Expansion, and CO 2 Dynamics: The Critical Role of Green Energy Consumption in the United States

This paper examines the nexus between transportation infrastructure, economic growth, and carbon dioxide (CO 2 ) emissions in the United States, with particular emphasis on the moderating role of green energy consumption (GEC). The United States is an economically advanced country with a well-developed transport infrastructure and sustained economic growth; however, this development has been accompanied by increasing environmental pressures, notably rising CO 2 emissions from the transport sector. Drawing on the Environmental Kuznets Curve (EKC) framework, the study investigates whether renewable energy sources—specifically wind, solar, and hydropower—can decouple economic growth from environmental degradation. A Vector Error Correction Model (VECM) was employed to analyze both short-run dynamics and long-run cointegrating relationships among transport infrastructure, economic activity, CO 2 emissions, and green energy consumption. The results indicate that relative to fossil-based energy, green energy significantly mitigates the emission-enhancing effects of transport infrastructure expansion and economic growth. These findings underscore the pivotal role of renewable energy in achieving sustainable development. From a policy perspective, the results highlight the importance of integrating green energy into national transport and infrastructure planning. Overall, the study demonstrates that in transport-intensive economies, the expansion of renewable energy does not constrain economic growth but is essential for ensuring its long-term environmental sustainability.