## 3 Methodology
### Life Cycle Inventory  
The data used for the analysis were directly provided by Nolpal and covers the period from June to December 2023. The dataset pertains to a single trademark industry managing 7915 shipments to almost 1000 retailers, with subsequent operations carried out at 38 Nolpal Points across Italy. This comprehensive dataset ensures a reliable and robust foundation for modeling environmental impacts. Due to the large volume of data, weighted average values were calculated for specific parameters, as reported in Table 1.  
The analysis compares the pallet use and transportation phases across the four pallet management systems previously described:  
* Scenario A: Standard Deferred Exchange;
* Scenario B: Standard Direct Exchange;
* Scenario C: Nolpal Deferred Exchange;
* Scenario D: Nolpal Direct Exchange. Since specific data on the types of trucks used for transportation were unavailable, the modeling assumes the use of EURO 6 lories. As stated by the European Automobile Manufacturers' Association, by 2025, Euro 6 heavy trucks will make up almost 60% of the EU fleet alone, standing as the most widespread type of heavy vehicles used [20]. In addition to this, according to the ANFIA (National Association of the Automotive Industry Supply Chain), heavy-duty vehicles with a weight exceeding 16 tons were by far the most diffused among industrial vehicles in 2023 in Italy, accounting for 83% of the total. Since our study considers data referring to 2023, EURO 6 lories within the 16-32 metric tons size class have been selected for the calculations [21]. As previously mentioned, this study focuses on EPAL1 pallets, whose specifications are summarized in Table 2.  
For practical purposes, the systems were divided into virtual subsystems called unit processes, with inputs and outputs identified for each. The four scenarios are composed of either four or two unit processes, depending on the number of trips in each scenario. The unit processes are defined as follows:  
* UP1 (Delivery of Goods Supported by Pallet): Common to all scenarios, this unit process involves transporting goods from the trademark industry to the retailer, located 300 km away. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Weighted Average Value** \\ \hline Number of pallets per cycle & \(11\) \\ Distance between trademark industry and retailer & 300 km \\ Distance between retailer and Nolpal Point & 50 km \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Parameters’ values. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Pallet weight & 25 kg \\ Safe working load & 1500 kg \\ Pallet dimensions & 1200 \(\times\) 800 mm \\ \hline \hline \end{tabular}
\end{table} 
Table 2: EPAL pallet specifications. * UP2 (Empty Return Trip of the First Lorry): Included only in Scenarios A and C, this process refers to the return trip of the empty lorry to the company. * UP3 (Empty Trip of the Second Lorry to Reach the Retailer): Exclusive to Scenarios A and C, this process accounts for the distance traveled by a second lorry to reach the retailer; varying based on the Nolpal Point is part of the system. * UP4 (Return Trip with Pallets Only on the Lorry): This process differs across scenarios. In Scenarios A and B, pallets are returned to the trademark industry.I In Scenarios C and D, the inclusion of Nolpal reduces the trip distance to 50 km, as the pallets are routed to the nearest Nolpal Point. Throughout this study, it was crucial to consider that while the use phase includes transportation segments where pallets are loaded with products--specifically UP1--the emissions impact is limited to those caused by the tare weight of the pallet on that loaded segment. This approach methodology aligns with numerous other studies in the field, which adopt a similar approach when calculating emissions during the use phase [22]. For the final modeling process, specifically the return trip of the lorry, a corrective factor of 0.8 was applied to the calculations.