Abstract
Circular economy is recognized as one of the most effective strategies for promoting plastic sustainability. However, its implementation requires to enhance consumer engagement, which remains a primary target of regulatory initiatives designed to promote plastic circular economy. To ensure sustained consumer participation, it is essential to evaluate and optimize various incentives, including regulatory policies, voluntary programs, and market-related mechanisms. This study applies Stackelberg Game Approach to quantitatively capture the strategic interactions between the authorities (as the leader) and consumers (as followers). The model incorporates key consumer behaviors, i.e., "use less," "use longer," and "recycling", to reflect their role in advancing plastic circular economy goals. By integrating factors such as governmental utility (gains of benefits), consumer utility (welfare), and plastic waste reduction, the model identifies the optimal intensities of various public initiatives, which represent the quantitative levels of policy intervention necessary to maximize desired outcomes. A case study based on EU-27 data demonstrates the model’s applicability, revealing optimal intensities of 0.91, 0.41 and 0.8 for regulatory, voluntary, and market-related initiatives. At these optimal intensities, regulatory measures achieve the highest governmental utility (benefits) and plastic waste reduction, while market-related mechanisms yield more favorable outcomes for consumer welfare. The findings highlight the need for a balanced policy mix that effectively aligns government objectives with consumer incentives.