Assessment of the Safety Impacts of Speed Limit Violations at Campus Mid-Block Crosswalks: The Case of Çukurova University

Creative Commons License

Yıldırım Z. B., Yıldırım C.

5th INTERNATIONAL CANKAYA SCIENTIFIC STUDIES CONGRESS, Ankara, Türkiye, 8 - 09 Aralık 2025, ss.314-324, (Tam Metin Bildiri)

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Basıldığı Şehir: Ankara
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.314-324
  • Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
  • Çukurova Üniversitesi Adresli: Evet

Özet

ABSTRACT

This study evaluates the impact of low-speed limits, commonly implemented on university campuses, on the safety performance of unsignalized crosswalks using Surrogate Safety Measures (SSMs). Çukurova University campus, a site with high pedestrian-vehicle interactions, was selected as the study area, and the campus road network was imported into the SUMO environment using OpenStreetMap (OSM) data. Due to the lack of real-time data, vehicle and pedestrian flows were represented through a stochastic demand model that generates random routes. Microscopic simulations were conducted for approximately 2,350 vehicles and 4,500 pedestrians. To isolate the effect of the speed parameter, four scenarios were defined in which the geometry and demand were fixed and only the maximum vehicle speed was varied: a 30 km/h base case and scenarios representing speed limit violations of 40, 50, and 60 km/h. The trajectory data obtained from the simulations were processed with a Python–TraCI-based module, and for each pedestrian event, time-to-collision (TTC) and Post-Encroachment Time (PET) were calculated. In the analysis, thresholds of TTC<2 s and PET<3 s were used as conflict indicators. The findings reveal a gradual but significant increase in the number of conflicts based on both TTC and PET as the transition from the 30 km/h base scenario to the 40, 50, and 60 km/h scenarios. It was determined that the number of conflicts falling below the critical TTC value increased significantly, particularly at speeds of 50 km/h and above, while PET values indicate a significant reduction in the time available between vehicles and pedestrians. The results demonstrate that a target speed of 30 km/h at campus pedestrian crossings is a significant safety threshold, as confirmed by SSM data, and that speed violations should be systematically reduced.

Keywords: Surrogate Safety Measures, Pedestrian–Vehicle Interaction, Time-to-Collision, Post-Encroachment Time, Traffic Safety, Speed Management