Assessing road criticality and loss of healthcare accessibility during floods: the case of Cyclone Idai, Mozambique 2019

Abstract

Background The ability of disaster response, preparedness, and mitigation efforts to assess the loss of physical accessibility to health facilities and to identify impacted populations is key in reducing the humanitarian consequences of disasters. Recent studies use either network- or raster-based approaches to measure accessibility in respect to travel time. Our analysis compares a raster- and a network- based approach that both build on open data with respect to their ability to assess the loss of accessibility due to a severe flood event. As our analysis uses open access data, the approach should be transferable to other flood-prone sites to support decision-makers in the preparation of disaster mitigation and preparedness plans. Methods Our study is based on the flood events following Cyclone Idai in Mozambique in 2019 and uses both raster- and network-based approaches to compare accessibility to health sites under normal conditions to the aftermath of the cyclone to assess the loss of accessibility. Part of the assessment is a modified centrality indicator, which identifies the specific use of the road network for the population to reach health facilities. Results Results for the raster- and the network-based approaches differed by about 300,000 inhabitants (~ 800,000 to ~ 500,000) losing accessibility to healthcare sites. The discrepancy was related to the incomplete mapping of road networks and affected the network-based approach to a higher degree. The modified centrality indicator allowed us to identify road segments that were most likely to suffer from flooding and to highlight potential backup roads in disaster settings. Conclusions The different results obtained between the raster- and network-based methods indicate the importance of data quality assessments in addition to accessibility assessments as well as the importance of fostering mapping campaigns in large parts of the Global South. Data quality is therefore a key parameter when deciding which method is best suited for local conditions. Another important aspect is the required spatial resolution of the results. Identification of critical segments of the road network provides essential information to prepare for potential disasters.

A global assessment of national road network vulnerability

“…This can be directly attributed to the relative size of the overall network compared to the size of the potential attack (disruptions of all roads within 5 × 5 km can cause very high levels of disruption in a small country). Given the geographical constraints on increasing the redundancy of the road network in SIDS, the priority should be to strengthen the most critical road segments while increasing inter-modal redundancy around the most critical clusters of roads (for example with water or air transport) to ensure that evacuation and access to health centres is possible in the case of a natural hazard (Rentschler et al 2021, Petricola et al 2022. Similar results and recommendations are valid for mountainous countries that are constrained in the kilometres of all-weather roads that can be built at an affordable cost (Oh et al 2019).…”

Translating Risk Narratives in Socio-technical Systems into Infrastructure Utilization Metrics during Compounding Hazard Events

“…These choices create negative consequences in the overall transportation system operations, hence the criticality changes from normal to disaster situations. One of the popular ways to find the criticality of the road network is to perform network analysis using topological credentials of the network elements (Sohouenou et al 2020;Petricola et al 2022) since there exist strong relationships between dynamic traffic flow patterns and the underlying transportation network structure (Hackl and Adey 2019). The topological credential of road network is defined as the identification of most critical and vulnerable components (e.g., road segment, intersections, etc.)…”

Quantitative Evaluation of Difficulty in Visiting Hospitals for Elderly Patients in Depopulated Area in Japan: Using National Health Insurance Data

“…These are important studies to evaluate public health services in emergency situations. Some studies have calculated accessibility to medical facilities considering earthquakes, floods, and landslides [26][27][28][29][30]. These studies take into account road closure, risk of damage, etc., and are important for maintaining the medical system in the event of a disaster.…”