VLDP Data sets
Description
Based on the data obtained from a freight transportation company that operates two lines, one of which has one-way transportation time of one day and the other with 2 days, we generated a set of benchmark VLDP data instances of three different sizes: small-sized (including 15 or 18 orders), medium-sized (20, 25, or 30 orders) and large-sized (40, 50, or 60 orders). The planning horizon is considered as seven days. Order related parameters are generated based on an analysis of the real data. We randomly selected some pairs of orders as related orders preferred to be transported by the same shipment, where the ratio of the number of related pair of orders to the number of orders varies between 0 and 0.32 in all instances as in the real data. The penalty associated with each additional distinct shipment day and each additional distinct shipment for related orders are set to $0.2$ and $0.1$, respectively. The vehicle fleet is assumed to be comprised of vehicles owned by the freight logistics company and rented vehicles. The unit cost of using an owned or a rented vehicle is $50 or \80, respectively. There are two types of owned or rented vehicles regarding their sizes and weight capacities: one type has a width of 5 units, a length of 25 units, and a weight capacity of 7500 units, and the other has a width of 5 units, a length of 30 units , and a weight capacity of 9000 units. The available day of an owned vehicle during the current planning horizon based on its delivery schedule in the previous planning horizon is determined according a procedure described in the related article of authors. The instances generated based on the above setting are considered as original instances and classified under group G1. Five additional groups of large-size data instances (Groups G2 to G6) are generated with controlled variety on sizes or due dates of orders in order to investigate the effect of the variety of sizes and the variety of due dates on the results. The details of the data set can be found in the related article of the authors.