## 1 Introduction  
In increasingly turbulent and volatile markets, where competition is no longer just between companies but between global supply chains, organizations must act to improve their performance and competitiveness [1]. In such a context, transport management has become a key element in the strategic agendas of companies and governments, not only from an economic perspective of cost reduction and service improvement but also increasingly as a means of reducing resource consumption, carbon emissions and traffic congestion [2, 3]. Urban freight transportation (UFT) is one of the main actors in the daily life of cities. New emerging business models, such as online sales, or traditional ones, such as physical trade and catering, have one important thing in common: their proper functioning could not take place without the support of a good distribution network since a good distribution network, compared to an inefficient distribution, allows to reduce costs and environmental impact [4] and to improve customer satisfaction [5]. The UFT is, therefore, a key link in the supply chain, but its influence goes much further due to its relationship with all the elements that make up the city [6]. In this respect, it is essential for companies to have resources that provide them with greater visibility into their logistics processes, enabling them to make decisions that contribute to optimizing their operations [7]. In addition, if companies want to maintain their competitive advantage, they must not only monitor the performance of their operations but also improve it. It is not always necessary to allocate resources to technology, equipment or facilities, but it is possible to increase process efficiency through sustainability-related improvements [8]. Consequently, the company needs to identify useful tools to measure the efficiency and productivity of a transport process in order to eliminate or reduce activities that do not add value to the process [9]. At present, there is a problem in urban freight transport as companies cannot measure efficiency because there are no efficiency meters in this area [10; 11], so we will develop an indicator to measure efficiency in this sector. OEE (Overall Equipment Effectiveness) is a concept commonly used in the industrial sector to measure the productivity and efficiency of equipment [12]. It is an essential indicator for companies that want to know their weak points or possible inefficiencies and implement improvement measures. This concept of OEE can be extended, albeit with some adaptation, to other sectors, not only industrial. In recent years, a large number of research papers [13] have been published on OEE, as well as case studies, implementations and new adaptations of OEE. OEE has been adapted to the needs of industry in various areas, such as line manufacturing [14], mining equipment [15] and assembly tasks [16]. There are also studies where OEE losses are evaluated in terms of energy consumption losses (ECL) [17] and economic losses (Cost Loss Indicator (CLI)) [18]. In the logistics sector, there is no defined methodology for its calculation [19]. Although there has been a great deal of research, there is no consensus, and in fact, the concept has not yet been fully developed in this field. These studies have worked on the definition of an OEE for transport [8; 20], where, instead of equating the vehicle with industrial equipment according to the classical concept of OEE, these studies focus on the analysis of the efficiency of each \"route\" individually [8] and on the analysis of the efficiency of the loading and unloading process of a truck [20], where it is observed that the efficiency does not depend only on the efficiency of the vehicle but also on that of the driver or that derived from other external factors. However, the OEE concept presented in both studies is designed for medium-distance logistics, and given the significant differences with UFT, it is not possible to apply such an OEE to the route of a medium-distance truck.