Optimization of drayage operations with time-window constraints

This paper addresses a version of the drayage problem in which the intermodal terminal requires trucks to have an appointment, and each truck must pick up or drop off the container at a customer location within a specified time window. This problem is mathematically formulated as an extension of the multiple traveling salesman problem with time windows (m-TSPTW). To efficiently solve the model, an algorithm based on reactive tabu search (RTS) is developed. The RTS solutions demonstrate that the developed integrated model is capable of finding the optimal solutions and is solvable within reasonable time for an operational problem. Experimental results indicate that (1) the appointment quota per time period set by the terminal operator has a significant effect on drayage operation time, (2) for a given change in appointment quota, there is no correlation between problem size and drayage operation time, (3) the adoption of an efficient truck appointment system could considerably reduce operation time for drayage firms, and (4) truck depots should be sited close to the terminal and empty container depot.