Integrated Shift Scheduling and Load Assignment Optimization for Attended Home Delivery

In this article, we study an integrated shift scheduling and load assignment optimization problem for attended home delivery. The proposed approach is divided into two phases, each one corresponding to a different planning level: tactical and operational. In the tactical planning, a daily master plan is generated for each courier. This master plan defines the working shifts, the origin–destination pairs to visit, and the number of client requests to serve. In the operational planning, delivery orders are allocated to couriers in real time. The stochastic and dynamic nature of client orders is included in the tactical and operational decision levels, respectively. Experimental results demonstrate that our approach provides robust tactical solutions that easily accommodate fluctuations in client orders, preventing additional costs related to the underutilization of couriers and to the use of external couriers to satisfy all delivery requests, when compared with an approach using the mean demand value. Moreover, these results also indicate that the failure to incorporate robust tactical solutions in the operational planning results in infeasible operational plans that are inadmissible regarding the couriers’ working time (e.g., minimum and maximum numbers of working hours) and work regulations (e.g., allocation of consecutive working hours to the couriers).