“…To the best of our knowledge, although some studies set the vehicle cost as their only objective [134,144,150,[174][175][176][177][178], the majority of the studies (54.3%) regard the vehicle cost as the part of fixed cost and aim to minimize the combination of the fixed cost with some variable costs, such as travelling cost [128,133,136,145,146,[179][180][181][182][183], penalty cost [184], inventory cost [163,[185][186][187], fuel cost [188], and emission [137].…”