Mechanical failures as a contributing cause to motor vehicle accidents – South Africa

Over the past decades motor vehicles became the primary mode of transportation in developing countries. At the same time an improvement in automotive engineering and manufacturing as well as the phenomena of urbanisation have resulted in more vehicles spending more time on the road at higher speeds. Invariably this leads to driving scenarios where safety critical manoeuvres have to be performed that rely on the mechanical condition of the vehicles. In developing countries, where economic realities force the population to make use of older and less reliable vehicles, the risk of accidents caused by some sort of mechanical failure increases. The casualty rate (events causing death and/or serious injuries) for road traffic accidents in South Africa is amongst the highest in the world. This trend has persisted with little variation over the years, despite the efforts of local road safety organisations and research institutes to decrease them. The main goal of this study was to establish the contribution of mechanical failures to motor vehicle accidents, and furthermore, to compare it with international trends. Data obtained from accident response units (ARU) indicate that tyres and brakes were the main contributors to mechanical failures resulting in accidents in the Pretoria region (Gauteng Province). However, the reported percentage of approximately 3% is comparable to similar statistics from developed countries. Detailed information on the condition of road-going vehicles was then collected in this area. The roadside survey (potential mechanical defect tests (PMDT)) indicated that 40% of the vehicles surveyed on the suburban road and 29% of the vehicles surveyed on the highway had mechanical defects that contravened current road and traffic regulations in South Africa and may, therefore, be at risk of causing an accident due to a mechanical failure. In the Minibus (taxi) survey, large irregularities in tyre inflation pressure were identified as a cause of concern. The main conclusion from this work is that tyres and brakes are the two most dominant components that contribute to the mechanical defects causing accidents, with overloading an additional factor to consider. It is important to acknowledge that these three factors can easily be monitored during simple roadside inspections.