The edge and the center in neighborhood planning units: assessing permeability and edge attractiveness in Abu Dhabi

Sustainable urban form research brought with it a renewed interest in neighborhood planning units (NPUs). While there is some insightful historical and qualitative research on the location of nonresidential uses in NPUs, quantitative analysis of the accessibility of nonresidential uses in NPUs has received minimal attention. This article uses Multiple Centrality Assessment to understand the accessibility of nonresidential land uses in NPUs designs. Using NPUs in Abu Dhabi as a case study, the paper analyzes different patterns of street networks across different scales and proposes new concepts and models for understanding accessibility. A framework for accessible NPUs focuses on three elements: street layout design, permeability, and edge attractiveness. Permeability is defined by high levels of Gravity and/or Betweenness at an NPU’s center at a global scale. On the other hand, the edge attractiveness that provides strong “seams” between NPUs is defined by high values of Gravity and/or Betweenness at an NPU’s edges and perimeter locations at a global scale. Findings suggest that a well-designed NPU must be characterized by both permeability and edge attractiveness. Results also indicate that nonresidential areas should be located according to their functions and level of intensity. Findings stress that at a local scale, NPUs should be designed to have high accessibility and low permeability for daily nonresidential facilities at the center. However, to promote the interconnection between adjacent NPUs, the street networks should have high accessibility and high edge attractiveness for nonresidential facilities located along the edges at a global scale. This research presents a conceptual approach and practical implications for planning NPUs’ nonresidential land uses and it contributes to the debate and practice on accessibility in an NPU.