Equitable last mile distribution in emergency response

In humanitarian emergency distribution, it is important to keep equity among delivery quantities and delivery times. In this paper, we consider a multi-period relief distribution network with time window and split delivery. We compare equity measures regarding delivery quantities, arrival times and deprivation times in different locations. We find that arrival time equity and deprivation time equity are equivalent under a certain condition. Moreover, we show that the equity measures behave differently depending on the ratios of supply, vehicle capacity and demand. Importantly, the deprivation time equity can better address the concept of "equity" in humanitarian emergency distribution. We conduct a case study on the Haiti earthquake to illustrate the impact of the proposed equity measures.