By using the interdiction technique on thousands of links, this paper shows how to select the most critical links. Ideally this phase would be conducted in close collaboration with policy makers, who are generally well aware of the most critical links and can bring nuances to the selection. Analysts can easily take into account additional qualitative information on the strategic or economic relevance of some links to improve the decisions. The combination of quantitative information on disruption costs and knowledge of the local challenges allows the identification of the most important areas of the network for further analysis.

This paper then demonstrates how to identify the most exposed of these links to natural hazards by overlaying the network with hazard data and factoring in different parameters of their vulnerability – such as flood depth and duration, traffic rerouting, and structural damage. Finally, by running hundreds of scenarios of possible events and their impacts, it applies a robust decision-making approach to guide an analysis of policy options available when a road network is exposed to unpredictable climate events.

More data are needed to evaluate the full economic and social costs of disruptions and improve the economic analysis on the most vulnerable links of Peru’s road networks. In addition, other nonengineering solutions exist to reduce the vulnerability of the critical links that could be as effective, if not more, as the options explored in this paper. They include reforestation, traffic management, and multimodality. Reforestation, for instance, could significantly reduce the risk of landslides. Finally, traffic management, particularly if linked to early warning systems, could reduce losses during a disaster, by redirecting traffic to alternative routes and lowering the costs of a disruption afterwards by avoiding congestion.

# 5. References

Bonzanigo, L., Brown, C., Harou, J., Hurford, A., Karki, P., Newmann, J., Ray, P., 2015a. South Asia Investment Decision Making in Hydropower. Decision Tree Case Study of the Upper Arun Hydropower Project and Koshi Basin Hydropower Development in Nepal (GEEDR South Asia No. AUS 11077). The World Bank.

Bonzanigo, L., Molina Perez, E., Ramos, C., Groves, D.G., Rodriguez Cabanillas, I., Kalra, N.R., Brandon, C.J., 2015b. Robust decision-making in the water sector: a strategy for implementing Lima’s long-term water resources master plan (No. WPS7439). The World Bank.

Briceño-Garmendia, C., Guasch, L. (Eds.), 2015. Analisis Integral de Logistica en Peru (Integral Analysis of Logistics of Key Export Products), World Bank, SECO. ed. Published by MINCETUR, Washington DC, USA, Lima, Peru.

Briceño-Garmendia, C., Moroz, H., Rozenberg, J., 2015. Road Networks, Accessibility and Resilience: The Cases of Colombia, Ecuador and Peru, Transport and ICT Global Practice and Chief Economist Office of the Latin American Region. ed. World Bank, Washington DC, USA.

Cervigni, R., Losos, A.M., Chinowsky, P., Neumann, J.L., 2016. Enhancing the climate resilience of Africa’s Infrastructure: the roads and bridges sector (No. 110137). The World Bank.

Cervigni, R., Morris, M., 2015. Enhancing resilience in African drylands: toward a shared development agenda. World Bank.

Espinet, X., Schweikert, A., Chinowsky, P., 2015. Robust Prioritization Framework for Transport Infrastructure Adaptation Investments under Uncertainty of Climate Change. ASCE-ASME J. Risk Uncertain. Eng. Syst. Part Civ. Eng. E4015001.

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