## 1 Introduction  
E-commerce has gained increased importance in several countries worldwide, and online initiatives have proliferated across different industries and sectors [1; 2]. This has led to a change of priorities and requirements in the overall logistics [3], resulting in the need for organizations to innovate their ways of creating value for their final customers by performing additional services in addition to the delivery of items, such as the collection of items [4] or installation or assembly service according to the items received [5]. Last-mile delivery, defined by [6] as the last trip the product takes before the final customer, represents one of the most critical activities for companies. Even though there are several definitions, a widely agreed one is that last-mile delivery refers to all logistics activities related to the distribution of shipments, i.e., parcels with items ordered by private customers to their houses in urban areas [7]. The adequate management of the processes behind the last-mile delivery affects the reliability, effectiveness, efficiency, and level of service of the delivery made to the final customer [8]. Considering the diversity of services, the rising number of orders, the higher customer expectations, and the low operation efficiency [9], it is critical that companies can manage human resources, fleets, and routes, among others, to guarantee a certain level of service. The level of service offered by an organization is assumed to depend on several factors related to the characteristics of the items sold, such as price, promotions, delivery, or assembly. Thus, it is expected that companies aim to increase their level of service to increase their profits [10]. Logistics is highlighted by [11] as a group of different activities that involve planning, implementing, and efficiently and effectively controlling the storage and flow of goods, services, and related information from the point of origin to the point of consumption to achieve the end customer requirements. Logistics services have a critical role within an e-commerce business and must implement innovative technologies in their logistics activities [12]. According to [13], even though they can provide the organization's end consumers with a better purchase experience, logistics services can additionally bring other challenges to organizations. One of the most critical challenges that logistics companies whose focus activity is on the delivery and collection of goods face is related to the vehicle routing problem (VRP) [14]. The VRP emerged from the traveling salesman problem [15], and in the classic VRP, vehicles perform deliveries from the depot, visiting one or more customers and then going back to the depot [16]. While the traveling salesman problem is made up of only one vehicle that visits multiple customers, the VRP is a problem made up of more than one vehicle [17]. As emphasized by [18], the VRP can be defined as the problem of designing the least costly delivery routes from a depot to geographically dispersed customers, subject to a set of rules and constraints. Since the early 2000s, the number of VPR variants has grown fast [19], which shows the diversity of its applications [20], and among these variations, Capacitated Vehicle Routing Problem (CVRP) or Vehicle Routing Problem with Time Window (VRPTW) are the most cited in the literature [18; 21]. On the one hand, as emphasized by [22], in the CVRP, goods need to be delivered to a set of customers with established demands, originating and terminating at a depot with the minimum-cost vehicle routes. On the other hand, VRPTW extends CVRPs by adding a time window associated with customers' different variations of the VRP, such as Distance-Constrained Vehicle Routing Problem, Vehicle Routing Problem with Backhauling [23], and Vehicle Routing Problem with Pick-up and Delivery [5; 23].