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Computer Modeling to Investigate the Risk of All-Terrain Vehicle Rollover While Turning

Friday, October 19, 2012
Room 272-273 (Morial Convention Center)
Charles A. Jennissen, MD, FACEP, Jonathon J. Marsico, John M. Steffen and Gerene M. C. Denning, Department of Emergency Medicine, University of Iowa Children's Hospital and University of Iowa Hospitals and Clinics, Iowa City, IA

Purpose: Rollovers are the most common all-terrain vehicle (ATV) crash mechanism, but field research is limited due to subject injury risk. Computer modeling is a potential tool to safely investigate ATV crash mechanisms and risk factors.  The purpose of this study was to explore how various factors might affect ATV rollover likelihood while turning.   

Methods: A computerized free body diagram was constructed of an ATV with passenger(s), and the risk of rollover with turning was assessed for multiple parameters while keeping ATV size specifications constant. 

Results: Surfaces with higher friction coefficients (i.e. dry pavement) increase the likelihood of a rollover while turning.  Even a typical dirt trail (friction coefficient of 0.3) would require a 16.4 mph limit to avoid a slide with an average adult male driver making a 60 ft. radius turn. A slide may not result in a rollover but will reduce the operators control over the ATV.  The risk of rollover increases significantly with tighter turns.  If the operator simply takes more gradual turns at higher speeds, roll-overs can be avoided entirely.  The minimum turning radius for most ATVs was around 8 ft. which only allows a maximum speed of around 10 mph to avoid a rollover on high friction surfaces.  As the combined operator/passenger weight increases from 85 lbs to 365 lbs, the vehicle speed needs to be reduced approximately 4 mph in order to prevent a rollover at the same turning radius.

Conclusion:   Surface friction, total rider mass, velocity and turning radius are rollover determinants that are terrain and rider decision dependent. Education of operators, enforcement of strict no passenger rules, and speed limiters for younger drivers may be important to affect these factors and prevent rollover crashes.  Manufacturers could engineer better rollover protection by optimizing ATV width and lowering its center of gravity, and/or producing ATVs with roll bars and safety belts.