In the output files 
we report the values for the following binary decision variables:

x#i#j#t  = 1 if truck i is assigned to driver j on day t (normal day shift)
x1#i#j#t = 1 if truck i is assigned to driver j on day t in the early shift
x2#i#j#t = 1 if truck i is assigned to driver j on day t in the late shift
xS#i#j#t = 1 if truck i is assigned to driver j at Saturday t