In this paper we analyze the total costs generated to low-temperature distribution companies by the transport in part load of perishable freight. Using the data of 2008, which have been directly obtained from a sample of transport companies, the social costs and the tariff system are estimated with the aim of accentuating the difference between the external costs and producer costs, and comparing them with final prices. According to those calculations we can state that current tariff system offers enough resources to cover the external costs.