Embedment of climatic effects in the road asset management process

Abstract

The United Nations Environmental Programme describes the African continent as a ‘vulnerability hotspot’ for climate change. During the past four decades African countries have experienced more than 1 500 recorded weather-related disasters. Changes to the region’s climate are causing widespread damage to road infrastructure and its associated assets. In order to help address this significant threat to Africa’s development, the Africa Community Access Partnership (AfCAP), a research programme funded by UKAid, has commissioned a project, starting in April 2016, to produce regional guidance on the development of climate-resilient rural access in Africa through research and knowledge sharing within and between participating countries. The output will assist to develop a climate-resilient road network that reaches fully into and between rural communities. As part of this study, a Climate Threat and Vulnerability Assessment Methodology has been developed that can be applied at a national level to facilitate the identification of regions/districts where the road infrastructure is most vulnerable to a changing climate in terms of the impact on rural accessibility. A second methodology for the assessment of climate risk and vulnerability of rural access roads at a local level has also been developed. Both the district level and local level assessments make use of climate threat data, road network data and socio-economic data. The outcomes from these assessments are a number of indices, both separate and combined, that can be used to rank roads and structures in terms of priority for maintenance or adaptation. Once roads and structures have been ranked in terms of priority for maintenance or adaptation and maintenance and adaptation activities can then be planned, designed and implemented to lead to a rural road network that is more resilient to the impacts of climate change. The district level assessment combines climate threat data and road network data (mainly road condition data) to determine road exposure to identified threats and from determine a road asset vulnerability index. The socio-economic data and road network data are combined to determine a road criticality index. A remoteness indicator expands on a standard RAI by measuring the level of access that a person living within an area (e.g. district) has to a range of services and other functions that are associated with an urban setting. A consolidated view of asset criticality per district is then formed by aggregating the road exposure and vulnerability index and the rural access index. The outcome of the local climate vulnerability assessment is a multi-dimensional vulnerability index. The vulnerability index integrates three composite indicators, namely an indicator of road condition deficiency to the impacts of climate, an indicator of maintenance efficacy, and an indicator of the criticality of the road. The deficiency index and the maintenance index is calculated using data that are gathered by way of a climate impact field assessment during which the road is assessed in 100 m segments. The criticality index is a combination of socio-economic aspects, namely the number of alternative routes available; predominant vehicle types on the road; public facilities reachable by the road; and the dominant topography surrounding the road. The assessment methods presented here should be embedded in road asset management systems, as these are the most appropriate vehicle to store the input data, perform the analysis and apply the outputs in the broader road asset management environment.