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During a motorcycle accident, a rider’s helmet may dissipate energy to reduce the likelihood of serious brain injury. Novelty helmets lack the energy-absorbing layer between the comfort liner and the outer shell of the helmet. In this study, we compared the injury mitigation capabilities and associated brain injury potential of novelty helmets to three US DOT-approved motorcycle helmets. The analysis was performed using a drop tower system. Helmeted Hybrid-III and magnesium head-forms were dropped onto a slab of asphalt with contact to the upper, back region of the helmets. The first drop height was chosen to simulate a fall from the typical seated height of a rider on a cruising style bike, and the second height was chosen to yield an impact speed that conformed to the DOT testing requirements, 6 meters per second (13.4 mph). Resultant accelerations, head injury criterion (HIC), and probability of an AIS 4+ brain injury were calculated for each drop test.

A 3-2-2-2 array of linear accelerometers and a combination of a triaxial linear accelerometer and a triaxial angular rate sensor were mounted into a Hybrid III 50th percentile male ATD head-form and compared in a variety of short- and long-duration events. An appropriate low-pass filter cutoff frequency for differentiating the angular rate sensor data into angular accelerations was found by using a residual analysis to find individual cutoff frequencies for the three center of mass (COM) linear accelerometer channels and the three angular rate sensor channels and taking the arithmetic mean of the six cutoffs. The angular rate sensors provide more accurate rotational rates than integrated angular accelerations calculated from arrays of linear accelerometers and are less cumbersome, especially for events lasting longer than 200 ms.