GIS-based evaluation of the speed limit increase on urban arterial traffic safety in Ankara

Kibar, Funda Ture
Tüydeş Yaman, Hediye
Setting safe speed limit is very critical and complex phenomenon, which has to be decided based on the road hierarchy that categorizes roads according to their functions and capacities, and poses certain restrictions in the design process. However, this is challenging in urban regions of developing countries, where rapid city growth forces high-speed intercity roads to serve as urban arterials, along which traditional 50 km/h limit is not practically possible. To lower the speed variation (and provide mobility), speed limit increase is allowed as high as 82 km/h as in the case of urban arterials in Turkey. To understand the real impact of such controversial countermeasures, which is the main scope of this study, spatiotemporal distribution of accident hotspots along urban arterials are analyzed in GIS using nearest neighbor hierarchical (NNH) clustering; changes between 3 years before and after periods are evaluated using as hit rate (HR), predictive accuracy index (PAI), and recapture rate index (RRI) indices. For a case study of 7 urban arterials in Ankara, NNH analysis (withn(min)= 5andd(max)= 250 m) resulted in 94 clusters in the before period, while there were 101 clusters in the after period; and decreasedPAIvalues in the after case showed more accidents in the clusters, demonstrated no real improvement by speed limit increase. Application of safe system approach in the critical hotspots also showed that speed limit increase on the study corridors in Ankara was against the safe limits suggested by UNECE based on possibility of certain accident types.


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The purpose of this study is to determine the most suitable remediation techniques for an active landslide area in Turkey, using a geological engineering assessment of a re-activated landslide that occurred during the construction of the Artvin-Savsat Junction on the Meydancik Provincial Road, at Km: 12 + 200. For this, the geotechnical parameters of the mobilized geological material-which is colluvium along the sliding surface-were determined by back analyses of the landslide at three geological sections. ...
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Investigation of Traffic Safety Effects of Speed Limit Increases in Main Arterials
Türe Kibar, Funda; Tüydeş Yaman, Hediye (2018-09-30)
Setting safe speed limits requires consideration of different factors (operating speeds, road hierarchy, etc.), especially in urban corridors. With a legislative change, speed limits were increased from 50 km/hr by 32 km/hr on some urban arterials in Turkey, effect of which is examined for Ankara urban arterials in this study. Shifts in traffic accident hotspots, which were determined using Nearest Neighborhood Hierarchical (NNH) Clustering in Geographical Information System (GIS) environment, are quantifie...
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A vast majority of studies on municipal solid waste (MSW) collection routing do not consider the constraints pertinent to actual road networks such as unidirectional roads and terrain characteristics. As a result, good practices such as the avoidance of U-turns cannot be used. This study introduces geographic information system (GIS)-integrated software (RouteSW) for the optimization of MSW collection routes by considering path constraints. The software uses a parallelized hybrid genetic algorithm (PHGA) to...
Citation Formats
F. T. Kibar and H. Tüydeş Yaman, “GIS-based evaluation of the speed limit increase on urban arterial traffic safety in Ankara,” ARABIAN JOURNAL OF GEOSCIENCES, pp. 0–0, 2020, Accessed: 00, 2020. [Online]. Available: