Decreasing computational times for solving static elevator operation problems by assuming maximum waiting times

In this paper, we propose a technique to decrease computational times for solving static elevator operation problems which are formalized as trip-based integer linear programming models. The technique is comprised of two parts: (i) to give equations which constrain the search space on the assumption that the maximum waiting time over passengers of an optimal solution is known, and (ii) to estimate such time as longest round-trip times. Computational results indicate that the technique can basically decrease computational times without degrading objective function values when maximum waiting times are less than estimated values and the number of equipped elevators is 1.