Abstract

The development of logistics has contributed a lot to all the branches of economy. A successful economic subject cannot exist without a well-developed logistic branch. The organization of logistics has become a strategic element of the policy making of enterprises. Modern logistics enables us to bring into line different interests in material flow management. Global organizers of logistic services are developing and specialising in some essential services, such as combining of cargo into assembly consignements and also their distribution. The biggest global tenderers of logictic services are considered (DHL, TNT, FEDEX, UPS, etc). Razvoj logistike je v veliki meri pripomogel k razcvetu vseh panog gospodarstva. Ni uspešnega gospodarskega subjekta, ki ne bi imel zelo razvito vejo logistike. V gospodarstvu postaja organiziranost logistike strateški element vodenja podjetij. Logistika torej sodi med tista področja, ki bodo pomembno vplivala na naše življenje, zato je razvoj logističnega sistema izjemnega pomena, tako za gospodarstvo kakor tudi za negospodarske dejavnosti. Torej nam sodobna logistika omogoča uskladitev različnih interesov v upravljanju materialnega toka. Razvijajo se globalni organizatorji logističnih storitev, ki se razvijejo in specializirajo na nekaj ključnih storitev, med katere spada združevanja tovora v zbirne pošiljke ter tudi sama distribucija teh pošiljk. Med največje globalne ponudnike logističnih storitev prištevamo podjetja kot so: DHL, TNT, FED EX, UPS ...

Abstract

In Southeast Asian cities, it is common for logistic companies to operate a heterogeneous fleet of delivery vehicles with motorcycles being the preferred vehicle to handle the final phase of delivery. In such scenarios, heterogeneous fleet vehicle routing problem (HFVRP) is generally applied to plan an optimal delivery. However, in many downtown cores of large and rapidly developing Southeast Asian cities, HFVRP is neither viable nor reliable because of road usage restrictions. The purpose of this article is to develop and test a different approach that accurately takes these restrictions into account and provides viable and more sustainable results. Restrictions in this paper refer to situations of urban areas in Vietnam where (i) certain vehicle types are prohibited in specified areas or where narrow alleyways limit the utilization of vehicles that exceed the road capacity and (ii) certain roads are exclusive to certain vehicle types. In networks, limited access and exclusive lanes are represented as links, or arcs, exclusive to one or another. Taking these limitations into consideration, we have developed a unique model, which we have termed Vehicle Routing Problem with Exclusive Links (VRP-EL). The model was validated and tested for its performance on scenarios with varying ratios of exclusive links. Scenarios up to 500 customers were tested on a meta-heuristic algorithm, simulated annealing. VRP-EL produces realistic outcomes. Limiting certain links to be selected according to vehicle types increases overall travel distance. However, this increase outweighs the cost of re-planning and rerouting had they not been constrained initially. The reduction in traveling distance leads to fossil fuel reduction for the overall system. The estimation of reduced carbon emissions through applying the proposed model is presented. Considering the severe traffic congestion and carbon emissions caused by motorcycles in Vietnam, the proposed model leads to a sustainable road environment. Document type: Article