The Skeletal Trap: Mapping Spatial Inequality and Ghost Stops in Ankara's Transit Network
Organizations: Independent Researcher, Ankara, Turkey
Abstract
Ankara's public transport crisis is commonly framed as a shortage of buses or operational inefficiency. This study argues that the problem is fundamentally morphological and structural. The city's leapfrog urban expansion has produced fragmented peripheral clusters disconnected from a rigid, center-oriented bus network. As a result, demand remains intensely concentrated along the Kizilay-Ulus axis and western corridors, while peripheral districts experience either chronic under-service or enforced transfer dependency. The deficiency is therefore not merely quantitative but rooted in the misalignment between urban macroform and network architecture. The empirical analysis draws on a 173-day operational dataset derived from route-level passenger and trip reports published by EGO under the former "Transparent Ankara" initiative. To overcome the absence of stop-level geospatial data, a Connectivity-Based Weighted Distribution Model reallocates passenger volumes to 1 km x 1 km grid cells using network centrality. The findings reveal persistent center-periphery asymmetries, structural bottlenecks, and spatially embedded accessibility inequalities.
Figures & tables
| Algorithm | Diagnostic Question | Type of Failure Detected |
|---|---|---|
| Autoencoder (PCA) | Does this grid’s ridership–frequency–occupancy relationship conform to the system’s normative logic? | Systemic logic failure : Locations whose supply-demand configuration cannot be reconstructed from the dominant latent patterns, indicating a breakdown in the system’s internal grammar. |
| Isolation Forest | Is this grid statistically extreme in the multidimensional feature space? | Extreme outliers : Grids occupying the far edges of the distribution, such as exceptionally high passenger loads paired with minimal trip frequency. |
| Local Outlier Factor | Does this grid deviate from its operational peer group? | Contextual neglect : Locations that appear normal in absolute terms but are anomalously underserved relative to grids with comparable density profiles. |
| Graph-based Spatial | Does this grid’s service profile diverge from its geographic neighbors? | Spatial discontinuity : Adjacent grid cells receiving dramatically different levels of service despite occupying the same urban fabric. |
| Algorithm | Diagnostic Question | Type of Failure Detected |
|---|---|---|
| Embedding Stability | Does this grid’s operational identity (ridership–frequency profile) remain consistent across days, or does it drift erratically? | Representational unpredictability : Locations that behave like a busy urban center on one day and a quiet suburban periphery on the next, preventing the system from establishing a stable reading of the grid’s identity. |
| Daily Clustering | Can the system consistently assign this grid to the same operational archetype each day? | Categorical instability : Locations whose assigned cluster oscillates between high-demand, low-service (deficit) and low-demand, low-service (normal) from one day to the next, indicating that the system cannot commit to a stable classification. |
Urban Planning
Urban planning uses geospatial data, machine learning, and optimization to analyze cities and guide transport, land use, housing, and climate decisions.
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