We investigate the problem of storage assignment in a warehouse served by milkrun logistics, i.e. vehicles circulating according to a pre-defined schedule between the warehouse and the production facilities of the plant. Such a logistic system results in an easy-to-characterize correlation among the request probabilities of the items in the warehouse. A MIP model is proposed that exploits this correlation for finding a class-based storage policy that minimizes the order cycle time or the average picking effort. Computational experiments show that our approach can achieve an up to 36-38 % improvement in either criterion compared to the classical COI-based strategy
