## 1 Introduction
Considering the practical aspect, it is envisaged that the main areas of analysis supported by the developed approach would be:  
* Scenario analysis of strategic decisions in the context of cost optimisation and quality performance of the postal operator's logistics network;
* Modelling the shape of the product portfolio in the context of service opportunities in the logistics network;
* The impact of the planned implementation of new services or acquisition of significant volumes from new customers on the cost position of services in the logistics network problems;
* The possibility of optimising the handling of individual products in line with the changing (increasing) quality requirements of the market, e.g., the possibility of changing the pick-up and delivery times of parcel shipments (of individual product groups) in different regions of the country and the delivery times (of individual product groups) in different regions of the country;
* Analysis of the possibility of bottlenecks in the logistics network with the expected increase in the volumes handled;
* Analysis of the schedules of planned investments in the network of logistics points, taking into account its efficiency parameters;
* Simulation of the demand for transport resources (quantity, type) and the feasibility of transport plans. Selection of optimal development models in the context of the adopted cost and environmental priorities. From an operations research perspective, delivery operations often boil down to vehicle routing problems that arise when goods need to be delivered to a number of delivery locations by more than one vehicle. This is precisely the kind of problem we consider in this work. Although this broad description covers a wide range of applications, it is often the case that a few specific business characteristics make it difficult to use the approaches associated with this problem, which in turn leads to the development of increasingly specific models that are more applicable to the practical problems faced by businesses. Over the past decades, the vehicle routing problem (VRP) with its variants has been very popular and addressed in publications by the scientific community [3; 4]. In [5], authors examine what is the optimal set of routes for a fleet of vehicles to traverse in order to deliver to a given set of customers. Since VRP is an NP-hard problem [6], exact algorithms are only efficient for small instances of the problem. Heuristics and metaheuristics are often more suitable for practical applications. As real-world problems are much larger in scale (e.g., a company may need to supply thousands of customers from dozens of warehouses, using multiple vehicles and under a variety of constraints). In the paper [7], the authors used a loading approach for both single and double-decker trucks to deliver goods on multicity routes. The primary objective is to meet both customer demand and delivery times. In [8], the authors investigate what is the shortest possible route for a single vehicle to visit each customer exactly once and returns to the source. In contrast, in the work [9; 10], the authors consider the Container Relocation Problem (CRP), also in maritime transport, using exact methods based on linear programming and heuristics. Containers transported to a container terminal are stored in container yards side by side and on top of each other, forming blocks. An important aspect of the logistics problems is the consideration of time and delays in the delivery of goods to the point of destination. This has been taken into account in the publications [7; 11], where in the latter, a new multi-objective path-finding model is proposed to find optimal paths in road networks with time-dependent stochastic travel times. This study is motivated by the fact that different travellers usually have different route-choice preferences, often involving multiple conflicting criteria, such as expected path travel time, variance of path travel time, and so forth.