Managing carbon emissions in urban mobility system: A credit-based reservation scheme

To mitigate carbon emissions and exploit underutilized lanes (e.g., bus lanes), a credit-based reservation scheme (CRS) is proposed to optimize road resources, allowing travelers to switch from the high-emission mode (e.g., driving in normal lanes) to the low-emission mode (e.g., taking buses) and gain carbon credits. These credits can then be used to access the reward mode (e.g., using priority lanes). This CRS design problem is formulated as a leader–follower game, where the transport authority determines the reward ratio based on the mode choices of travelers. We analyze how the CRS affects emissions and traffic congestion, and conduct two numerical studies on Beijing and London to verify our findings. Results demonstrate that when the reward ratio is set at a moderate level and the generalized cost of the reward mode is higher than the other two modes, the CRS can effectively reduce system-wide carbon emissions and traffic congestion.