The Impact of Government Subsidies and Carbon Taxes on Emission Reductions for Intermodal Transport Operator and Carrier

To address carbon emission challenges in the transportation sector, intermodal transport—which enhances both economic and environmental benefits—is becoming ever more crucial. Governments often implement policies like subsidies or carbon taxes to steer intermodal transport towards sustainable development. This paper constructs a Stackelberg game model involving an eco-conscious shipper, an intermodal transport operator, and a carrier to analyze the combined economic and environmental impacts of carbon taxes, subsidies, and their dual-policy implementation on the intermodal transport system. The results of the study were as follows: (1) While either carbon taxes or subsidies alone enhance emission reduction and freight volume, their dual implementation generates synergistic effects, achieving superior emission reduction and freight growth; the study also challenges conventional wisdom by demonstrating that “reducing subsidies for intermodal transport may promote carbon reduction in transportation, while increasing taxes does not necessarily disadvantage logistics companies.” (2) Governments can achieve a win–win outcome for the economy and the environment by first prioritizing the increase of carbon taxes to effective levels, and guiding carriers to bear higher emissions reduction costs, before increasing subsidies. (3) Continuously enhancing shippers’ environmental awareness can effectively reduce total emissions. However, its impact on profits depends on the decision-making mode (decentralized vs. centralized) and the cost sharing among logistics companies. (4) There exists an optimal value for the intermodal operator’s share of emission reduction costs. Values that are too low can weaken the incentives for emission reduction, whereas values that are too high may harm profits. This research quantifies the complex interactions among policy combinations, consumer preferences, and enterprise cooperation modes. It offers valuable guidance for governments to design precise emission-reduction policies and helps upstream–downstream enterprises in intermodal transport systems optimize their operational strategies.