Analysis of the relationship between fatal rural road crashes and road design elements: Namibian case study

Ambunda, Robert (2018-12)

Thesis (MEng)--Stellenbosch University, 2018.

Thesis

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.

AFRIKAANSE OPSOMMING: Verkeersveiligheid is 'n groot kommer in ontwikkelende lande. Elke jaar word meer as 1.2 miljoen mense in padongelukke in die wêreld doodgemaak. Die ongeluksterftesyfer in Namibië is na berig word hoër as die Afrika-kontinentale gemiddeld van 27, by 31 sterftes per 100 000 inwoners. Die studie het gefokus op die ontleding van die verhouding tussen noodlottige padongelukke en padontwerp-elemente vir die studieperiode tussen 2013 en 2016 op die Namibiese landelike padnetwerk. Padafdelings met die hoogste noodlottige ongelukkoerse is geïdentifiseer om die potensiële verhouding tussen die noodlottige ongelukkoerse (afhanklike veranderlike) en padontwerpelemente (onafhanklike veranderlikes) te bepaal. Negatiewe Binomiale Regressie is gebruik om die statistiese korrelasie en betekenis van die impak van die padontwerpelemente op die voorkoms van noodlottige ongelukke op die leergedeeltes te assesseer. Die studie het vasgestel dat die radius van die horisontale krommes, toegangsbeheer en die 85 persentiel-bedryfspoed 'n beduidende invloed het op die voorspelling van noodlottige padongelukke op paaie met 'n laanwydte (LW) van meer as 3.5m. Die studie het bevind dat padblootstelling (padlengte en volume) 'n beduidende impak-ongeluk risiko vlak en voorspelling op pad afdelings met 'n baan wydte gelyk aan of minder as 3.5m. Die studie het bevind dat 40% van die leergedeeltes nie voldoen het aan die Tegniese Aanbevelings vir Hoofweë 17-riglyne (TRH 17) op laanwydtes nie, terwyl die helfte van die leergedeeltes nie voldoen het aan die TRH 17 riglyne ten opsigte van die onbeheerde skouer breedte. Die studie het ook vasgestel dat 90% van die leergedeeltes 'n onderontwikkelde skouerkruisval het. Opmetings is uitgevoer op twee padafdelings met LW1 <3.5m> LW2 om die oorsaak van noodlottige ineenstortings te ondersoek. Meer as negentig persent van die respondente in elke leergedeelte het bevind dat die afdelings onveilig is. Roekelose en nalatige bestuur is aangehaal as die hoofveiligheidsprobleem op beide studie-paaie. Die meerderheid van die respondente het erken dat hulle bewus was van die beduidende impak wat padingenieurswese en -ontwerp op die veiligheid en operasionele doeltreffendheid van 'n pad het. Die meeste van die ondervraagde deelnemers was van mening dat die verhoging van die teenwoordigheid van wetstoepassing die bestuurders sou weerhou om onveilige bestuursgedrag aan te gaan.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/105066
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