Investigation of when quad bikes rollover in the farming environment

[Display omitted] •Quad bikes are vulnerable to a rollover event when traversing relatively small bumps on typical grassy slopes at moderate speeds.•The results suggest that workplace users of quad bikes need to seriously consider whether this type of vehicle is safe for performing their required workplace tasks.•If it is likely that the vehicle will be used on rough/uneven moderately sloping terrain with the potential for distracted riding, it appears that a quad bike is not a suitable vehicle for the task. Quad bikes, referred to as All-terrain vehicles (ATVs) in North America, are the leading cause of fatalities and serious injuries on Australian farms and on–farms in many other countries. These fatal and injurious events have been associated with riding over bumps such as rocks, tree stumps, grass tufts, etc., specifically bumps positioned in-line with one wheel track of the quad bike that can result in a rollover trapping the rider. Earlier work presented Finite Element simulations showing how a quad bike and seated rider travelling over the bump on flat terrain can induce sudden steering and yawing that consequently triggers a rollover event. This study identifies which combination of speed, slope and bump size causes a quad bike with a seated rider to rollover. Two different rollover mechanisms occur depending on the speed, slope angle and bump height: a rear wheel impact steering induced rollover mechanism; and a front wheel impact tip-over mechanism. When quad bike speed and the slope steepness are increased to typical values (e.g. 20 km/h and 12.5°), the bump size needed to cause a rollover quickly reduces (e.g. around 100 mm). Quad bikes are particularly vulnerable to a rollover event when travelling around farming environments where they traverse relatively small bumps on typical grassy slopes at moderate speeds. This suggests that a quad bike should no longer be considered as a vehicle fit for farming tasks and alternate safer vehicles should be considered.