## 1 Introduction  
Container drayage refers to the short-distance transportation of containers using trucks, which has become an indispensable part of modern globalized supply chains and logistics networks. While container shipping covers long-distance transportation, drayage is responsible for connecting and transferring containers between container terminals and their customer locations, making it an essential link in the door-to-door service. Due to the limited capacity of trucks compared to container ships, the prosperity of container transportation has led to an increased number of trucks on the road, exacerbating traffic congestion and elevating carbon emissions [1]. Furthermore, despite its relatively short transport distances, drayage accounts for 25% to 40% of the total container transportation cost [2], while empty container transport makes up approximately 40% of drayage operations but generates no revenue [3]. As global trade volumes continue to rise, optimizing drayage operations has become increasingly critical to reducing overall transportation costs and carbon emissions, especially as demand for more efficient and sustainable solutions intensifies. The optimization of container drayage operations essentially involves the allocation of empty containers, the dispatching of trucks, and the routing or sequencing of truck pickups and deliveries among container terminals, railway hubs, inland depots, and customers. Initially, the CDP was viewed as a one-to-one pickup and delivery problem in the pioneering research that began in 2002 [4], which is defined as picking up a container from a dedicated origin and delivering it to a specified destination. After this initial breakthrough, researchers soon recognized the significance of differentiating container status and flow direction, such as full or empty, inbound or outbound, resulting in eight types of common transport requests. Among these, six basic types of requests--inbound full (IF), empty repositioning (ER), empty demand (ED), outbound full (OF), inbound empty (IE), and outbound empty (OE)--refer to the transport of containers from an origin to a destination without intermediate nodes, while two types of composite requests--IFER and OFED--involve the combination of two basic requests. An IFER request requires an inbound full container to be delivered from a terminal (IF), and once emptied, the container must be repositioned to a depot or an alternative site (ER). On the contrary, an OFED request demands an empty container to be delivered to a shipper (ED) and after packing, the outbound full container should be delivered to the terminal (OF) [5]. IF, ER, ED, OF, IFER, and OFED requests are defined from the perspective of customer scheduling, while IE and OE requests are clarified from the standpoint of the shipping company. The handling of composite requests gives rise to two common trucking operation modes (Stay-with and Drop-and-pull) [6], while the combination of requests related to empty container repositioning and demand brings about two empty container repositioning strategies (Depot-turn and Street-turn) [7], both of which significantly increase the complexity of the CDP. A large body of research has investigated the CDP in recent decades [8; 9]. However, most existing studies focus on only a subset of these transport requests, which simplifies the modeling process but limits the model's ability to reflect real-world practices. For example, [PERSON] et al. [10] considered four types of requests (IFER, OFED, IE, and OE) and developed a determined-activities-on-vertex (DAOV) graph-based model. Nevertheless, their model is too brief to explicitly describe the detailed drayage operations, especially the allocation of empty containers. [PERSON] et al. [5] constructed a generalized model for the CDP with four single requests (IF, ER, ED, and OF) and two composite requests (IFER and OFED), but they assume predetermined origins and destinations of all requests. Similarly, [PERSON] et al.