Events such as Hurricanes Katrina and Rita in 2005 have highlighted the need to understand network disruptions, in particular in the humanitarian supply chain. Humanitarian supply logistics cannot be improvised at the time of the emergency since little can be done after a disruption occurs. Therefore, special attention should be given to preparedness efforts and the design of the supply chain network. Inventory prepositioning is one of the strategies in the preparedness stage that enhances postdisaster response because it reduces the lead time needed to reach the affected destinations once a disaster has occurred. In this paper, the prepositioning of supplies for disasters is modeled as a facility location problem that accounts for the routing of vehicles and possible disruptions in the transportation network. The approach uses a combination of the most reliable path and an integer programming model to find the optimal location of supplies. The problem is solved on an example transportation network. The problem exploits a variant of the shortest-path problem and can be solved efficiently even for medium and large-scale transportation networks.

This paper examines the chief findings of research conducted on policies to foster off-hour deliveries (OHDs) in the New York City metropolitan area. The goal was to estimate the overall impacts of eventual full implementation of an OHD program. As part of the research, a system of incentives was designed for the receivers of deliveries the system combined Global Positioning System (GPS) remote sensing monitoring with GPSenabled smart phones to induce a shift of deliveries to the off-hours from 7:00 p.m. to 6:00 a.m. The concept was pilot tested in Manhattan by 33 companies that switched delivery operations to the off-hours for a period of 1 month. At the in-depth interviews conducted after the test, the participants reported being very satisfied with the experience. As an alternative to road pricing schemes that target freight carriers, this was the first real-life trial of the use of financial incentives to delivery receivers. The analyses indicate that the economic benefits of a full implementation of the OHD program are in the range of $147 to $193 million per year, corresponding to savings on travel time and environmental pollution for regular-hour traffic as well as productivity increases for the freight industry. The pilot test also highlighted the great potential of unassisted OHDthat is, OHD made without personnel from the receiving establishment present-because almost all participants who used this modality decided to continue receiving OHD even after the financial incentive ended.

Assessing the importance of transportation facilities is an increasingly growing topic of interest to federal and state transportation agencies. In the wake of recent terrorist attacks and recurring manmade and natural disasters, significant steps are needed to improve security at both state and metropolitan level. This paper proposes a heuristic procedure using concepts of complex networks science to assess the importance of highway transportation networks using travel time as the performance measure to assess criticality. We demonstrate the proposed technique both in a theoretical network (Sioux Falls network) and in a built-up network to assess the criticality of the major infrastructures that are used to access Manhattan in an AM peak hour. The results demonstrate the efficacy of the procedure to determine critical links in a transportation network.

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