Department of Civil Engineering

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Browsing Department of Civil Engineering by Author "Ambunda, Robert"

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    Analysis of the relationship between fatal rural road crashes and road design elements: Namibian case study
    (Stellenbosch : Stellenbosch University, 2018-12) Ambunda, Robert; Sinclair, Marion; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: Traffic safety is a major concern in developing countries. Every year over 1.2 million people are killed in road crashes in the world. The crash fatality rate in Namibia has been reported to be higher than the African continental average of 27, at 31 fatalities per 100 000 population. The study focused on analysing the relationship between fatal road crashes and road design elements for the study period between 2013 to 2016, on the Namibian rural road network. Road sections with the highest fatal crash rates were identified, to determine the potential relationship between the fatal crash rates (dependent variable) and road design elements (independent variables). Negative Binomial Regression was used to assess the statistical correlation and significance of the impact of the road design elements on the occurrence of fatal crashes on the study sections. The study established that the radii of the horizontal curves, access control and the 85th percentile operating speed have a significant influence in predicting fatal road crashes on roads with a lane width (LW) greater than 3.5m. The study found that road exposure (road length and volume) has a significant impact crash risk level and prediction on road sections with a lane width equal to or less than 3.5m. The study found that 40% of the study sections did not comply with the Technical Recommendations for Highways 17 guidelines (TRH 17) on lane widths, while half of the study sections did not comply with the TRH 17 guidelines with regard to the unsurfaced shoulder width. The study also established that 90% of the study sections have an under designed unsurfaced shoulder crossfall. Surveys were carried out on two road sections with LW1<3.5m> LW2 to investigate the causation of fatal crashes. More than ninety percent of the surveyed participants on each study section found the sections to be “unsafe”. Reckless and negligent driving was cited as the main safety issue on both study road sections. The Majority of the surveyed participants admitted that they were aware of the significant impact that road engineering and design has on the safety and operational efficiency of a road. Most of the surveyed participants were of the view that increasing the presence of law enforcement would deter drivers from engaging in unsafe driving behaviour.