Sequential auto carrier loading problem

Sequential auto carrier loading is a postprocess of the auto carrier loading problem (ACLP) and can be formulated as an integer programming problem for each auto dealer along the auto carrier route except the dealer that is the last stop. The associated objective function for each individual subproblem is to minimize the number of reloads and, for those vehicles that are reloaded, to minimize the total arcs in the path from the reassigned slots to the exit slot. The sequential ACLP (SACLP) process also relaxes the assumption made in the literature that if at any auto dealer a vehicle is unloaded and reloaded again, it is reloaded back to its original slot. To solve the SACLP, an iterative heuristic algorithm that takes into consideration the effect of empty slots is proposed. At each auto dealer, after its demand has been unloaded, any unloaded vehicles destined for the upcoming dealers are reloaded back to better unassigned slots on the auto carrier and are subject to various loading constraints. Computational experiments on fve instances indicated that use of the SACLP improved the solutions obtained from the ACLP by itself.