# Synchromodal Supply Chains for Fast-Moving Consumer Goods
## 2 Literature Review
### Concept of Synchromodality  
Synchromodality addresses a pivotal aspect in the transportation research debate: identifying the most efficient and effective combination of transport modes [16]. Even though synchromodality is the most recent modal shift paradigm, it is essential to point out that there is a plethora of legacy logistics paradigms implying the use of modal shifts, including multimodality, intermodality, combined modality, and comodality [17]. These paradigms can be defined as follows:  
* Multimodality is the transportation of goods by a sequence of at least two different transport modes [17];
* Intermodality is the transportation of goods integrating at least two modes such that the load is transported door to door using the same load unit [18];
* Combined modality is a sustainable form of intermodal transportation [19];
* Comodality is efficient transportation through optimal and sustainable use of resources [20]. A recent study summarized the difference between synchromodality and legacy modal shift paradigms, which allows us to view synchromodality as the outcome of the evolution of modal shift paradigms [2]. Initially focused on improving the efficiency of the transport system, these paradigms have gradually evolved and come to incorporate multiple objectives to optimize the tradeoff between efficiency, service levels, and sustainability [11]. Table 1 highlights these differences with regard to such capabilities as integration, sustainability, efficiency, and flexibility. Integration is the process of connecting decisions and actions across an end-to-end supply chain to drive total value for all stakeholders. This process involves strategy alignment, effective management of operations, and maintaining reciprocal flows of information among stakeholders [21]. The definition of integration in the context of synchromodality and multimodal transportation can be narrowed down to the process of connecting different modes of transport to create a single, seamless transportation system. Integration of the modes of transportation can also involve the real-time coordination of schedules and other logistical factors [22]. Synchromodality is also closely associated with the concept of flexibility, which refers to the ability of a transportation network to shift modes and routes to accommodate changes in demand or unexpected events. The flexibility in a broader sense can also include the ability to adjust the number and type of vehicles. Efficiency refers to the ability of the supply chain network to minimize delays, reduce costs, and increase service levels. Efficiency can also be viewed in light of the efficient utilization of resources under various constraints and tradeoffs [23]. For example, synchromodal solutions are especially sensitive to the tradeoff between transportation and inventory holding costs because as companies ship more frequently or use faster modes with smaller maximum capacity, transportation costs tend to increase, but inventory costs decrease. However, if the priority is given to slower modes that can carry larger order quantities, the transportation costs decrease, but inventory costs increase due to the increase in cycle stock. Additionally, safety stock also becomes larger due to the longer lead times and increased lead time variability [24]. Sustainability, in general, refers to the ability to meet the needs and aspirations of the present generation without compromising the resources needed for future generations to meet their needs [25]. In the context of synchromodality, sustainability refers to the ability to maintain or improve the overall environmental impact of a supply chain without undermining its efficiency [26]. At first glance, it may sound counterintuitive, but in many cases, there is a congruence between environmental costs and financial costs related to transportation and logistics. For example, faster modes of transport (such as trucks) use more fuel and have much larger carbon footprints compared to slower modes of transport (such as ships and railways) [27].