Definition, Integration and Effectiveness of Integrated Green-Grey Infrastructure in Residential Street Retrofits: A Systematic Literature Review

Suburban residential streets have long been criticised for their multiple short-comings, including traffic-related injury, increased stormwater runoff, and lack of aesthetic values. Research suggests that Integrated Green-Grey Infrastructure (IGGI) is likely to play a role in mitigating these problems. IGGI refers to infrastructure that consists of both natural materials (such as plants, soil) and human-made structures (such as concrete, pipes). However, IGGI’s definition remains vague, and little is known about its implementation in suburban street retrofitting, and how effective it is. Using a systematic literature review method, this paper analyses peer-reviewed journal articles published over a period of ten years between 2014 and 2023. The objective was to understand IGGI’s definition, integration, and effectiveness in implemented residential street retrofitting projects. Through a rigorous screening process, 15 papers were selected for qualitative analysis. Clusters developed in analysing the results consist of IGGI’s concepts, components, integration and effectiveness. The most notable subject area is system-scale integration, shared by 14 papers. Findings regarding the effectiveness of IGGI suggest strong empirical evidence related to stormwater management and road user behavioural change; however, there were mixed perceptions toward the aesthetic values of rain gardens.