Rescheduling production and outbound deliveries when transportation service is disrupted

Unexpected service disruptions in transportation systems caused by accidents, system breakdowns, poor weather conditions, etc., are quite common. When disruptions occur, rescheduling of vehicles is often needed in order to mitigate the damage caused by the disruptions. In integrated production and outbound distribution systems, a disruption in outbound distribution operation affects not only the delivery plan but also the production schedule. In this paper, we consider a simple integrated scheduling model of production and outbound deliveries with a minimum headway constraint between vehicle departures, and study the situation where an optimal solution of the integrated scheduling model has been obtained but the delivery service is suddenly unavailable for a certain time period due to some unexpected incidents. We would like to determine a new production and delivery schedule in which no delivery takes place during the unavailable period. The objective is to simultaneously maintain a low cost schedule and control the magnitude of changes in the delivery times of the finished goods. We consider three different ways to control the time disruption, and develop polynomial-time algorithms for the corresponding problems.