Geospatial Analysis of Traffic Crashes at Curved Road Segments in Oyo State, Nigeria

Abstract

The road transport mode is the most accessible and widely utilised globally, yet it poses significant challenges to health and safety due to traffic crashes. While many studies examine the causes of road traffic crashes (RTCs), few focus on the influence of Curved Road segments using GIS-referenced data, particularly in developing countries like Nigeria. This study employs GIS and statistical techniques to analyze the impact of Curved Road segments and speed limits on RTCs in Oyo State, Nigeria, from 2020 to 2022. An ex post facto research design was adopted. Crash data sourced from the Federal Road Safety Corps (FRSC) included attributes such as date, time, location, crash type, causes, casualties, and weather conditions. Shuttle Radar Topographic Mission (SRTM) elevation data tagged crash sites, while road network and land use data from Landsat imagery were integrated using ArcGIS 10.8. The Getis-Ord G statistic identified 66 crash blackspots across 18 routes. Also, 55% of the curved road sections on the route under study are unsafe when driving at a speed between 80 and 100 km/h, while 45% are safe when driving at a speed between 60 and 80 km/h.  An independent t-test confirmed a significant disparity between FRSC-approved speed limits and curvature design at curved road segments (p = 0.000). The study concludes that roadway environmental factors strongly contribute to RTCs in Oyo State. Recommendations include enhanced patrol of crash blackspots, redesigning hazardous curves, frequent road maintenance, and improved signage to mitigate crashes. These measures are vital to improving road safety in the region.