# DMRVR: Dynamic Milk-Run Vehicle Routing Solution Using Fog-Based Vehicular Ad Hoc Networks
###### Abstract
However, aspects such as multiple depots, different types of commodities, and time windows complicate the model to solve the VRP. Given the variation of collection times, the total pickup time limit required by the OEM company is not always fulfilled by the operator, compromising agreements, and the OEM production line. Transporting goods from the OEM company suppliers is complicated, requiring strict logistic operation quality control for all parties [5; 7; 8; 10]. In dynamic vehicle routing problems (DVRP), not all relevant information for the routing process is known when the planning begins, and they can change after the initial route [9; 11]. DVRP requires solutions that work in real-time, using algorithms that meet these features. In dynamic routing systems, customers may have their requests rejected if they are unable to be added to the initial route. This would offer the possibility for the request to be serviced in the next day. In cases where the request is urgent, the logistics operator can forward it to a competitor [9] or send it to an auxiliary vehicle [11]. The complexity of dynamic vehicular routing problems is directly associated with the number of requests, the customer's geographical distribution, and the number of dynamic events to be considered. The complexity of logistics, and its importance as one of the main economic activities of the supply chain, enhance the role of information and communications technology (ICT) as a means of improving the visibility, responsiveness and efficiency levels in the supply chains that depend on transport operations [12]. Intelligent transport systems (ITS) has become the next big transportation management initiative in Europe and other parts of the world and an important step are the vehicular networks for the realization of the ITS. In order to maintain information updated in the routing system, a communication between vehicle and logistics operator is essential. Ideally, vehicle position must be known by the logistics operator at any given time for decision-making [9]. The use of Vehicular Ad hoc Networks (VANETs) in ITS applications allows for efficient milk-run operations by enabling updated data in real-time management tasks. For many ITS applications, VANETs became an essential pillar because they enable vehicle to vehicle communication (V2V), as well as communication between vehicle and infrastructure (V2I) [13; 14; 15]. In a vehicular network, there is no central coordinator for communication. Although some applications use roadside units (RSUs), these applications are expected to work with reliability using decentralized communication. The adoption of VANETs generates deployment and setup costs, but, after installation, it will help to improve shared resources and reduce the transportation and logistics costs [16]. In VANETs, the nodes do not need to get authorization to enter the network and send messages, and they can disconnect at any moment [17; 18]. This type of communication allows vehicles to share different types of information, as safety for accident prevention, post-accidents messages, or traffic jams [14; 17]. Dynamic network topology based on vehicle mobility and the impact of radio propagation on the environment is another challenge [17]. The vehicular networks must work appropriately in a range of conditions, including sparse and dense vehicle traffic. The use of VANETs in logistics scenarios was previously studied by [12; 19; 20]; however, in these works, milk-run operations were not addressed as the main focus. Some vehicular applications require communication between vehicles located in a specific geographical area or location. If there is a traffic jam or an accident, all vehicles around the event should be warned. For the vehicles moving away from this area, this information is not relevant. For these types of applications, GeoNetworking is an adequate choice [21]. GeoNetworking protocols are composed of a set of features that use vehicle geographical information for ad-hoc communication.