Investigation of Quad bike handling characteristics and their implications for on road use

Quad bikes or All-Terrain Vehicles (ATVs) continue to be a significant cause of serious injuries and fatalities in many countries. Of particular concern are injury incidents related to quad bike use on-roads. Results from the University of New South Wales (UNSW) Quad Bike Performance Project identified that most commercial quad bikes tested, demonstrated an oversteer steady-state handling characteristic. A mathematical relationship exists between a vehicle's oversteer characteristic and a 'critical speed' at which the quad bike is at risk of suddenly losing control. Theoretical analyses indicated that the critical speed for the tested quad bikes ranges between 26 km/h and 35 km/h. Computer simulations were also performed to determine whether quad bikes can safely interact with speed humps and roadside structures such as kerbs and traffic islands. The simulations indicated that quad bikes could traverse on-road speed humps without displacing the rider off the seat. However, traversing roadside structures such as a kerb or a pedestrian island, resulted in the displacement of the rider off the seat and in one instance a rollover. The results suggest that quad bikes are unsafe for on-road use where speed limits have been set to 50 km/h or more and where there are road features such as kerbs and traffic islands that need to be negotiated by the rider. In summary, quad bikes are vulnerable to the speeds and roadside structures found in the on-road environment.