## 2 Materials and Methods
### Characterisation of Selected LUZs  
The analysis of the loading and unloading zones in the city of Zaragoza is shown below. This city was chosen because it is a pioneer in mobility initiatives, such as the implementation of an Urban Consolidation Centre (CCU) in combination with PMVs for UDG [41], distribution pilots using autonomous robots [42], autonomous buses [43], and collaborations with the General Directorate of Traffic (GDT) [44; 45], which has selected it as a test laboratory. Additionally, the city participates in national and European projects such as URBANDUM [46] and DISCO. Based on the 2018 Sustainable Urban Mobility Plan (PMUS) [47], in the section on UDG, and using open data from Zaragoza City Council, 779 LUZs have been identified. [48; 49]. The average length of LUZs in the 14 areas defined in the PMUS in the urban area of the city is 19.4 m and the average time reserved is 7.7 h. Considering that this includes recently urbanised areas with very large spaces and generous times for loading and unloading, the central area, with 19.6 m and 6.5 h, seems to be a representative area for the study. In this area, 108 LUZ were identified, representing 13.86% of the 779 areas. Article 93 of Zaragoza's 2024 Urban Mobility Ordinance [50] establishes the maximum time allowed for loading and unloading goods as 30 min in general terms. This article is based on field research with direct observation in five LUZ in the central area. These areas were chosen for their representativeness:  
Zone 1:  
One-way street with free parking, 9.2 m wide in total and 5.3 m between vehicles, allowing for comfortable double parking. In addition, opposite the LUZ there is a 'dark  
Figure 1: Chart of the OEE model applied to a loading and unloading area. store' (an urban warehouse supplying stock to Glovo delivery drivers using PMVs), which generates high demand for supplies. The operating hours for this areaare from 9 a.m. to 12 p.m. and from 2 p.m. to 5 p.m. It is a 13-metre area, corresponding theoretically to space for threevans or trucks. The entire street, excluding garage entrances and pedestrian crossings, including both pavements, is 168 m long. Zona 2:  
A six-lane avenue, with three lanes in each direction, features regulated parking that also allows frequent double parking. The reservation time for loading and unloading is from 8 a.m. to 11 a.m., only in the morning. The avenue only has vehicles parked on one side, as the other side is dedicated to a bike lane, and has a total length of 173 m reserved for parking. The length of the loading area is 10 m, for two theoretical unloading spaces. Zones 3, 4 y 5:  
One-way street with free parking and no double parking, with cars on both sides of the street, with a total length of 165 m dedicated to parking. The three areas are: a first area of 18 m, with 4 theoretical spaces assigned and reservation times from 7 a.m. to 12 p.m. and from 2 p.m. to 5 p.m., a second 10 m zone for two theoretical spaces, from 9 a.m. to 12 p.m. and from 2 p.m. to 5 p.m., and a third 8-metre zone (reduced due to the allocation of a few metres to a bar terrace) for a single theoretical space, with the same hours as the previous zone. On this street, illegal parking occurs in front of garage doors, pedestrian crossings and at the intersection with the adjacent street. Figure 2 below shows a map of the area with the LUZ marked in red:  
The five areas have been selected for their variety, both in terms of the width of the streets where they are located and the possibility of double parking as an alternative to LUZ, as well as in terms of LUZ sizes. It is also taken into account that one of the areas is in a regulated parking zone. The fact that they are so close together makes it easier to collect data simultaneously in all five areas. They are considered to offer a representative sample of the city's LUZs. Table 2 compares the zones, highlighting the differences in the characteristics of each street and each zone. Figure 2: Aerial view of the area where the five zones are located.