“…However, the problem in which two or more assembly lines (parallel or multiple lines) may be present has not been widely studied as yet. This type of system has a higher equipment cost (Daganzo and Blumenfeld, 1994) but is both more reliable and more flexible (Rekiek et al, 2002;Becker and Scholl, 2006;Chiang et al, 2007) and allows for better balances, reducing the total number of required stations (Chiang et al, 2007). It also increases productivity (Chakravarty and Shtub, 1988;Boysen et al, 2006;Chiang et al, 2007), worker satisfaction and product quality (Ellegard and Jonsson, 1992).…”