TRACING URBAN MORPHOLOGY TOWARDS SUSTAINABILITY ACROSS SPACE AND TIME: EVIDENCE FROM A RAPIDLY GROWING U.S. METROPOLITAN REGION

Candidate Name: Erfan Kefayat
Program: Public Policy
Committee Chair: Dr. Jean-Claude Thill
Committee Members: Dr. Isabelle Nilsson, Dr. Michael Ewers, Dr. Ming-Chun Lee 
Abstract: Urban morphology drives a wide range of environmental and socio-spatial functionalities in
urban systems, while its multifaceted developmental trajectories towards sustainability have
received insufficient attention in the context of fast-growing metropolitan areas. This dissertation
presents a multi-layered spatio-temporal analytical framework for exploring Sustainable Urban
Built Morphology (SUBM), utilizing development tracts in Mecklenburg County, North Carolina
from 1990-2023. SUBM is defined through ten morphological measures spanning Built-up Tissue
Configuration, Land Use, and Transportation and Accessibility dimensions. Structured as three
complementary pieces of research, this dissertation investigates the temporal dynamics across
these measures, constructs a SUBM composite score, detects latent morphological regimes, tracks
their spatial dynamics, and describes localized development dynamics embedded in those regimes
across the study area. The first research longitudinally assesses SUBM measures and identifies
distinct morphological regimes, ranging from peripheral fragmented developments to a highly
integrated urban core. Based on a composite score, the study indicates that SUBM improved
overall, particularly from the early study period to the middle of the 2010s across the county. Such
improvement is mainly due to enhancement in compactness, density, and street-network
connectivity of the tracts. Yet recent SUBM trends suggest emerging divergence between tract-level
intensification and broader metropolitan settings. While tracts have maintained progressive
compactness and density, they are gradually emerging in less dense, peripheral, and poorly
accessible urban areas. The second study applies an Exploratory Spatio-Temporal Data Analysis
(ESTDA) framework to investigate heterogeneous and path-dependent dynamics of regimes across
the county. The results reveal unique pathways in which low-sustainability regimes displayed
scattered dynamics across the fringe of the county, whereas high-sustainability regimes
highlighted consolidated concentration patterns surrounding the urban core and the rail transit
corridor. This pattern emerges along with diverse concentration patterns across other regimes as
well. In the third research, the regime-specific tracts are clustered across space and time and
defined as Development Morphology Units (DMUs) to describe the localized spatio-temporal
patterns within each regime. Employing Spatio-Temporal Density-Based Spatial Clustering of
Applications with Noise (ST-DBSCAN) to define the DMUs, the results reveal that local growth
patterns follow distinct patterns, distinguished by their temporal occurrence, lifespan, spatial
extent, and spatial movement. Collectively, the study indicates that transition towards
​​​​​​​sustainable-oriented urban morphology is shaped by the interplay among the morphological characteristics,
their spatial dynamics, and fine-grained development trajectories. This study enriches urban
morphology scholarship through reinterpreting SUBM as a multi-faceted and multi-scale dynamic
and by offering a scalable analytical framework for assessing urban morphology trajectories
towards sustainability across space and time. The findings suggest that planning policies may be
better informed by incorporating urban morphology dynamics into the assessment of sustainable
urban development.