“…Heuristic algorithms such as simulated annealing (SA) (Chiang and Russell, 1996;Koulamas et al, 1994;Osman, 1993;Tavakkoli-Moghaddam et al, 2006), genetic algorithms (GAs) (Baker and Ayechew, 2003;Osman et al, 2005;Thangiah et al, 1994;Prins, 2004), tabu search (TS) (Gendreau et al, 1999;Semet and Taillard, 1993;Renaud et al, 1996;Brandao and Mercer, 1997;Osman, 1993) and ant colony optimization Reimann et al, 2002;Peng et al, 2005;Mazzeo and Loiseau, 2004;Bullnheimer et al, 1999;Doerner et al, 2004) are widely used for solving the VRP. Among these heuristic algorithms, ant colony optimizations (ACO) are new optimization methods proposed by Italian researchers Dorigo et al (1996), which simulate the food-seeking behaviors of ant colonies in nature.…”