This paper is a literature review focused on permeable pavements and especially the permeable subbase material. Run-off water from the surface is traditionally let through a drainage system, and the roads are kept dry. Due to climate changes, heavy precipitation and high-intensity rainfalls are putting pressure on the infrastructure. Traditionally, water in subbase materials reduces the resilient E-moduli and the lifespan of the pavement design. Studies show that increasing saturation reduces the bearing capacity of a traditional subbase material. Unbound materials with highly grained fines and high moisture content have higher tendency to show reduced resilient E-moduli. One study was found where the E-moduli of five different coarse grained aggregates used in permeable pavements were examined through a triaxial test. It was found that the E-moduli varied from 110–371 MPa. Other studies examining the E-moduli of permeable subbases based on moisture content were not found. However, this paper discusses different experiences regarding the bearing capacity of traditional vs. permeable subbase materials. It also covers a discussion and an analysis of missing research areas that needs to be investigated for further knowledge about the usage of permeable pavements in areas with a risk of flooding.

This paper contains an interview-based study focusing on permeable pavements as part of sustainable drainage systems. Climate change is causing pluvial flooding, according to the newest IPCC report. This mostly affects urban areas in cities due to: (1) limited capacity of existing drainage systems during heavy-intensity rainfall over a short period of time and (2) limited space for ditches in city areas. Permeable pavements are, therefore, sustainable drainage solutions which combine road infrastructure with water infrastructure. Are permeable pavements a preferable sustainable solution? To answer that question, 24 respondents were interviewed. The interview study was based on a semi-structured interview methodology. A lessons-learned experience was gathered, and the following conclusions were contrived: Firstly, official guidelines on how to construct, consult, and maintain permeable pavements are required. Secondly, more contractors should be able to offer the same product. Finally, official guidelines on the relationship between the contractors are required. These three indicators were extracted from the study.