## 4 Discussion  
It is no surprise that the illegal occupation of LUZs by private non-commercial vehicles and the excessive use by transport operators are the main causes of poor LUZ performance. One of the contributions of this work is the proposal of a methodology to quantitatively evaluate and enable the comparison of the behaviour of an area or set of areas using the OEE indicator. To do this, the key is the introduction of the new weighted occupancy time KPI, in which each vehicle contributes its length over the period of time it occupies the area. Evaluating separately and then jointly the availability of each zone, its occupation efficiency, and the quality of deliveries in terms of completion within the allowed time provides very valuable information for decision-making. Similarly, being able to evaluate each zone separately, as well as the performance of the zones based on booking times and days of the week, also provides relevant information for assessing the performance of the zone. Finally, temporal versatility is also an important factor. Each zone can be evaluated during a morning or afternoon slot, a full day, a week, a month, or any other relevant time frame. Focusing on illegal occupation, it should be noted that in Zone 1, only 7.7% of the area is dedicated to LUZ (13 m of the 168 m dedicated to free street parking); in Zone 2, this figure is 5.7% (10 m out of 173 m of regulated parking on the avenue); and in Zones 3, 4, and 5 combined, it is 21.8% (18 + 10 + 8 m out of the 165 m of street space). It is a significant finding that of the 472 instances of illegal parking observed in Zone 1 (a one-way street with the possibility of double parking), 38.77% (183) involved double parking, while only 3.81% (18) involved illegal parking in front of garage doors, on pavements, or on pedestrian crossings In contrast, in the streets correspondi ng to Zones 3, 4, and 5, where double parking is not possible, illegal parking accounted for 17.22% (140 out of 813). The street with the three zones and alarger total LUZ allocation still had three times more illegal parking than Zone 1, indicating that the impossibility of double parking leads to a significant increase in illegal parking in unauthorised areas, regardless of the size of the space reserved for LUZ on the street. The field study carried out shows that the use of free parking by private vehicles and inconsiderate transport operators leads to poor management of LUZ and generates externalities such as double parking and illegal occupation of pedestrian crossings, garage doors, and intersection islands. However, this study has detected deliveries by delivery drivers, especially from the HORECA sector, who double park even when there are spaces available in the LUZ in order to minimise walking distances and due to the heavy weight of the goods they have to deliver. The proposed KPIs are applicable in urban environments in any area of the city and allow for the evaluation of the suitability of the location and size of the area. They can be used for a single area or to compare a set of areas. These parameters and the proposedmethodology respond to the limitations that other authors have expressed in the literature discussed throughout the article. This method of calculating the OEE indicator is valid for any city, for an area or for a set of areas, and is therefore considered a very useful tool for city governance. As a general rule, both the location and size of the space reserved for the LUZ, as well as the time allocated for loading and unloading, are generally applied in cities in a generalised manner and without objective and quantifiable criteria for measuring them. This proposed methodology allows city authorities to make informed decisions regarding urban mobility regulations and could be particularly valuable for improving the management of low-emission zones to ensure better utilization. The main limitation of this study lies in data collection, which was manual, tedious, and labour-intensive.