Geographical epidemiology of road safety in Nigeria: The importance of weighted accident severity risk index in spatiotemporal analysis and injury epidemiology

Abstract

AbstractRoad safety is an essential indicator of quality of life. This study compared the Chand and Alex severity index with the Equivalent Traffic Accident Number's (ETAN) severity index to understand the spatiotemporal pattern of road traffic crashes in Nigeria. Weighting road crash data could help mitigate road crash risk and improve road safety measures. The weighted crash ratios were calculated based on crash data available between 2012 and 2016. Six factors identified from the literature were used as denominators in deriving these ratios. The sum ratios were ranked and mapped for cross‐temporal examination. There was no significant difference between the two methods for assessing accident severity index in this study. Univariate and multivariate spatial analyses were used to detect the hotspot of the weighted crash severity index (WCSI) for the end of the study period. Only the pairwise comparison analysis found a significant difference between the 2012 and 2016 WCSI (p < 0.05). Multivariate regression identified significant associations between youth literacy, speed violation, tyre blowout, and weighted severity index. Geographically weighted regression indicates that their local effects vary across spatial units. Information obtained from this study is essential for developing strategies towards achieving safe roads in Nigeria and contributes to injury epidemiology research.