“…Numerous variants of VRP have been introduced for many years in the literature. The variants of classical VRP problems can be classified as (see also Figure 1) capacitated VRP (Letchforda & Salazar-González, 2015;Wei et al, 2015;Cardoso et al, 2015), VRP with time windows (Hong & Park, 1999;Qi et al, 2015), VRP with pickup and deliveries (Dimitrakos & Kyriakidis, 2015;Avcı & Topaloglu, 2015), VRP with backhauls (Goetschalckx & Jacobs-Blecha, 1989;Ropke & Pisinger, 2006;Wang & Wang, 2009;Yalcin & Erginel, 2015;Koc & Laporte, 2018), open VRP (Zachariadis & Kiranoudis, 2010;Aksen et al, 2007;Brito et al, 2015;Erbao et al, 2014), VRP with multiple depots (Montoya-Torres, 2015; Chan & Baker, 2005;Ghafurian & Javadian, 2011), and VRP with the heterogeneous fleet (Koc et al, 2015;Salhi et al, 2014). Furthermore, VRP with time-dependent travel times has been studied recently because travel times are also dependent on the traffic congestion of the roads, which is based on queuing theory (van Woensel et al, 2007;van Woensel & Cruz, 2009;Oyola et al, 2018 for review).…”