Introduction: Urban growth in Africa is increasing mobility demand, with high-volume transport infrastructure developed to cope with stress on existing infrastructure. Such infrastructure development often entails risk accumulation (i.e. the potential build-up of vulnerabilities, hazard and negative externalities), and associated impacts on adjacent communities. This paper investigates how high-volume transport road infrastructure impacts the resilience, environment, and well-being of communities during the construction phase, including reactions/adaptations to the development of such projects. The paper uses the case study of the Missing Link #12 bypass in Nairobi, Kenya, where the development passes through the informal settlement of Kibera. Methods: The study uses an explanatory sequential mixed-method approach to explore the wider socio-economic, transport, and environmental impacts during the construction of the Missing Link #12 on the community of Kibera. Data collection comprises a survey with 452 households, six focus groups and a community engagement workshop. Results: The Missing Link #12 has had a divisive socio-economic effect on Kibera's community, due to spatial relocations, loss in livelihood, and breakdown in community social cohesion and interaction. While under construction, the road was not physically closed, but used by residents as non-motorized transport infrastructure, leading to increased walking and improved access to popular transport options. Health concerns linked with environmental risks of increased exposure and vulnerability to air and noise pollution emerged strongly, together with road safety issues caused by the shared environment with motorized transport modes. Conclusions: The case study shows the importance of accounting for risk accumulation for road-building infrastructure projects, starting from construction stage. Infrastructure development in African cities must be more inclusive and take into account the impacts on local communities, with success measured beyond the goal of reducing traffic congestion for car-owners. This is particularly true where more vulnerable and disenfranchised populations like in informal settlements are affected.

The frequent occurrences of bridge fires and the substantial disruptions and direct/indirect economic losses resulting from these events highlight the immediate need for effective fire-safety-oriented design of new bridges and retrofit approaches for vulnerable existing bridges. In this Perspective, we discuss why a holistic engineering approach integrating innovative fire analysis methods and structural design/retrofit strategies into multi-hazard and future-oriented risk modeling frameworks represents the way forward to more sustainable and resilient infrastructure in an uncertain and rapidly changing built environment. Bridge fires cause significant disruptions and economic losses in modern society, yet fire hazards are still often ignored or oversimplified in bridge design. This Perspective emphasizes the need for more holistic and comprehensive fire-safety design when retrofitting or designing new bridges.

Drawing on collective experience from ten collaborative research projects focused on the Global South, we identify three major challenges that impede the translation of research on sustainability and resilience into better-informed choices by individuals and policy-makers that in turn can support transformation to a sustainable future. The three challenges comprise: (i) converting knowledge produced during research projects into successful knowledge application; (ii) scaling up knowledge in time when research projects are short-term and potential impacts are long-term; and (iii) scaling up knowledge across space, from local research sites to larger-scale or even global impact. Some potential pathways for funding agencies to overcome these challenges include providing targeted prolonged funding for dissemination and outreach, and facilitating collaboration and coordination across different sites, research teams, and partner organizations. By systematically documenting these challenges, we hope to pave the way for further innovations in the research cycle.

The long-term goals and objectives that infrastructure projects aim to deliver are contextualised by complex grand challenges, which involve an entanglement of economic, social, and ecological issues. However, there have been criticisms that infrastructure projects fall short of delivering equitable value to effectively address grand challenges. These criticisms underpinned the recent calls for rethinking the purpose and definition of infrastructure projects. This essay argues that adopting a political ecology perspective can be useful to start identifying the limitations of the current understandings of external stakeholders and value in infrastructure projects, which lead to the criticised shortcomings. Political ecology considers social, ecological, and economic issues as an assemblage that manifests through power relations. Thus, for project studies, it implies a reconceptualization of external stakeholders and project value around the notions of agency, vulnerability, and empowerment. This reconceptualization provides new theoretical and practical directions for project formation, stakeholder management and project leadership in the pursuit of rethinking the purpose and definition of infrastructure projects for effectively tackling the grand challenges of our times.

This paper investigates the use of a citizen science approach for air quality monitoring to explore the likely pollution impacts of the new Missing Link #12 road passing through the informal settlement of Kibera, within Nairobi. Citizen science approaches are gaining relevance in air quality monitoring thanks to the advancement in environmental monitoring technology and the opportunities created for community-based organizations to collect data on air pollution through low-cost sensors. Fourteen households located in proximity to the Missing Link#12 were equipped with optical particle sensors. Data collected indicated that people living along the road are exposed to levels of PM2.5 and PM10 above WHO recommendations, mainly due to the particulate generated by the construction site and fuels used for indoor cooking. A community engagement workshop revealed that participatory approaches are useful for improving awareness of air pollution and associated health implications. It also allowed the community to enhance their capability to gain and use scientific tools to address local issues, and potentially lobby decision-makers to solve them. In the context of transport infrastructure development in African cities, such an approach can be a means of collecting data and monitoring the impacts of air pollution during and after road building.

This paper introduces a methodology to explore pedestrian accessibility in informal settlements. This methodology is applied to pandemic intervention sites in Nairobi's Kibera area for 3.5 months (14 April to 31 July 2020) during the COVID-19 pandemic. Freely available transportation network data and open-source GIS software are utilised. Isochrones, areas of equal travel time, are calculated to assess pedestrian accessibility (walk times) from 30,231 Kibera structures to 138 COVID-19 stationary intervention sites. These sites aid in virus control, resource distribution, and COVID-related medical support. Travel times are determined considering different terrain slopes. Unequal access to intervention sites is observed due to indirect routes. Shortest walks (up to 21.5 min) are to handwashing and food distribution points, while longer walks (up to 61.5 min) are to interventions with fewer sites or localised clustering, such as baby product distribution. This simple accessibility analysis helps identify service gaps during crises, aiding planning authorities and communities. Our methodology offers insight into travel patterns in slums and has wider applicability to assess the relationships between transport infrastructure provision and resilience in informal settlements.

Overlapping conditions of rapid urbanisation and climate change across developing countries are threatening the capacity of cities to manage climate risks, especially in the flood-exposed low-income peripheral areas. Limited studies have applied hydrodynamic flood models in ascertaining flooding conditions, supportive of risk-informed decisions in such urban fringes. Against this backdrop, we assessed plausible flooding and hazard conditions in the low-lying villages of Lindi and Silanga in Kibera informal settlement. The coupled one-dimensional and two-dimensional hydrodynamic model, customised from the Hydrological Engineering Centre's River Analysis System (HEC-RAS) was parameterised for flood simulation under different hydrological regimes and scenarios associated with flooding in Kibera. Volumetric flow estimates and a computed energy slope were used to define the upstream and downstream modelling boundary conditions respectively. Trial-and-error adjustment of the flow resistance coefficients from land-use features was applied in model calibration, and the results compared to the surveyed flood of 23rd April 2019. Results show that proximal areas to the Ngong River and Nairobi dam face high flood risks. A flood volume of 11.7×105m3 from a 2.5h, 50 mm rainfall could potentially inundate about 2.0% and 8.3% of areas in Lindi and Silanga respectively, while a volume of 48.9×105m3 from a 100-year storm of 172 mm could inundate about 10.6% of Lindi and 29.1% of Silanga. Upstream steeply sloping topographies of the villages increase flood velocities and risk of drowning, while the lower reaches at relatively flatter topographies, experience attenuated flow and rapid accumulation of flood waters, hence, higher flood depths. These results can support policy interventions for integrated flood risk management in Kibera, as a way of mainstreaming the underserved urban communities in climate risk management.

The increasing number and complexity of urban risk and disasters have a significant bearing on the emotional and mental wellbeing of those who are exposed and hamper their responses. Nevertheless, current discourses and approaches to increase resilience tend to focus on broader socio-economic, physical and environmental systems. This reflects a failure by the academic and practitioner communities to consider the potential contribution of human interior dimensions in adaptation planning. Concomitantly, a growing body of knowledge highlights the need to bridge the gap between internal and external (systems) approaches for achieving sustainable transformations. Against this background, this article aims to increase knowledge on the operationalization of such more integrative approaches in marginal settings. Based on a case study of a flood adaptation project in Kibera, Kenya, we assess the need and potential ways to address interior dimensions in the context of project planning, design and implementation. We show how the integration of such dimensions occurs in existing adaptation projects and why this matters. On this basis, we provide methodological and operational recommendations regarding ways to support more integrative approaches that bridge subjective, intersubjective, objective and interobjective perspectives to support transformation. 

While the amount of research on NBS is growing rapidly, there is a lack of evidence on community experiences of NBS design and implementation, particularly from low-income and informal settlements of African cities. This article adds new empirical evidence in this space through grounded analysis of NBS "niche" projects co-developed by intermediary organizations and communities in five sites across three settlements in Nairobi and Dar es Salaam. Findings are organized around four established NBS knowledge gaps: (1) NBS-society relations; (2) Design; (3) Implementation; (4) Effectiveness. We find that across the five studied sites, residents' perceptions and valuation of urban nature has changed through processes of co-design and co-implementation, enabling community ownership of projects, and hence playing a crucial role in NBS effectiveness over time. The integration of gray components into green infrastructure to create hybrid systems has proven necessary to meet physical constraints and communities' urgent needs such as flood mitigation. However, maintenance responsibilities and cost burdens are persisting issues that highlight the complex reality of NBS development in informal settlements. The cases highlight key considerations for actors involved in NBS development to support the replication, scaling up and institutionalization of NBS. These include the need to: (i) develop forms of engagement that align with co-production values; (ii) capture communities' own valuation of and motivations with NBS development for integration into design; (iii) elaborate technical guidance for hybrid green-gray infrastructure systems that can be constructed with communities; and (iv) help define and establish structures for maintenance responsibilities (especially governmental vs. civil society) that will enhance the environmental stewardship of public spaces.

This paper explores the changes in mobility and associated impacts in informal settlements arising from COVID-19 measures implemented in Kenya. Based on data from ten focus group discussions held in Kibera, Nairobi, we find that the dusk-to-dawn curfew and the increased costs of travel reduced the number of journeys and access to transport options, with consequent changes in mobility and increased time spent to travel. Such changes led to significant loss of income and reduced access to opportunities. This increased the already existing high level of poverty in Kibera and exacerbated individuals’ economic vulnerability.