Life cycle assessment and life cycle costing of road infrastructure in residential neighbourhoods

Purpose The built environment consists of a huge amount of infrastructure, such as roads and utilities. The objective of this paper is to assess the life cycle financial and environmental impact of road infrastructure in residential neighbourhoods and to analyse the relative contribution of road infrastructure in the total impact of neighbourhoods. Methods Various road sections are analysed based on an integrated life cycle approach, combining life cycle costing and life cycle assessment. To deal with complexity, a hierarchic assessment structure, using the principles of the "element method for cost control", is implemented. Four neighbourhood models with diverse built densities are compared to gain insight in the relative impact of road infrastructure in neighbourhoods. Results and discussion The results reveal important financial and environmental impact differences between the road sections analysed. Main contributors to the life cycle financial and environmental impact are the surface layer and electrical and piped services. The contribution of road infrastructure to the total neighbourhood impact, ranging from 2 to 9 % of the total cost, is relatively limited, compared to buildings, but not negligible in low built density neighbourhoods. Conclusions Good spatial planning of the neighbourhood is recommended to reduce the amount of road infrastructure and the related financial and environmental impact. The priority should be to design denser neighbourhood layouts, before decreasing the financial and environmental impact of the road sections.