Time-Series Analysis of Road Network Expansion and Urbanization Trends in Ankara

¹ Ankara Science University, Vocational School, Department of Unmanned Aerial Vehicle Technology and Operations, Ankara, Türkiye
² Ankara Yıldırım Beyazıt University, Faculty of Engineering and Natural Sciences, Department of Electrical and Electronics Engineering, Ankara, Türkiye
³ Ankara Yıldırım Beyazıt University, Faculty of Engineering and Natural Sciences, Department of Civil Engineering, Ankara, Türkiye

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

This study uses historical OpenStreetMap data and geospatial network analysis to examine Ankara, Türkiye, road network growth from 2007 to 2025. Yearly highway snapshots are reconstructed to quantify total network length, annual expansion rates, highway-type composition, and directional growth patterns. Projecting all geometries into a metric coordinate system ensures precise length estimation, and spatial differencing between years identifies new roadway segments. The results indicate a nonlinear expansion trajectory with distinct growth phases, including rapid development during the early-to-mid 2010s followed by more gradual expansion in later years. Residential and tertiary roadways have grown the most, showing urban and suburban connectivity demands contributed to expansion. Directional analysis reveals pronounced anisotropy, with dominant expansion toward the northeast and east, consistent with Ankara’s major urban development corridors. To contextualize infrastructure growth, June-month Normalized Difference Built-up Index (NDBI)–based built-up ratios were extracted annually from Landsat imagery. While there is short-term correlation between highway expansion and built-up development during periods of rapid growth, this relationship does not persist over time, indicating that highway expansion in Ankara is primarily influenced by infrastructure-led planning rather than short-term urban densification. Future studies should use direction/corridor-specific built-up indicators to examine spatially varied urban responses to anisotropic highway growth.