Introduction

With the overall number of traffic accident deaths on the decline in recent years, the number killed while riding two-wheeled motor vehicles has also fallen. Nevertheless, deaths of motorcycle and moped riders and passengers still totaled a significant 1,313 in 2004.   Safety helmets, which have greatly helped reduce motorcycle and moped accident casualties, were worn by more than 98% of all riders and passengers in 2004. The importance of wearing a helmet when on a two-wheeled motor vehicle may thus appear to be well understood, but this is not entirely true. In 27% of motorcycle accident fatalities, helmeted riders or passengers were killed because their helmets came off upon impact. In many of these cases, the outcome would have been less serious if the helmets had stayed in place.   This issue analyzes the frequency of helmet ejection, its effect on injury, and why such ejection occurs.   Riders and passengers are encouraged to use this information to minimize injury in case of accidents.

We have so far studied the circumstances of helmet ejection in terms of the frequency and degree of injury.   This section looks at the causes of helmet ejection in terms of helmet type and how they are worn.   Of the 426 moped and motorcycle accidents studied by the Institute for Traffic Accident Research and Data Analysis in the Tsukuba area of Ibaraki Prefecture from 1993 through 2004, 368 accidents in which it is known whether helmet ejection occurred or not, are analyzed.                Conclusion   Do you think helmet ejection will never happen to you?   If you think that you can avoid a major traffic accident, or that your helmet would probably stay on, or that even if it came off, it would at least protect you from the first impact, you're wrong.   Helmet ejection can occur in any type of moped or motorcycle accident, even at low speed.   If the chin strap is fastened loosely, the possibility of helmet ejection is high, particularly for helmets that cover the minimum area of the head. If the chin strap is not fastened at all, even a full face helmet can come off.   You cannot expect sufficient impact absorption from a helmet that is not fastened properly, as the helmet will shift easily due to the impact of the collision. Moreover, your head may receive more than one impact. (Impact absorption tests require that a helmet be hit twice at each test spot.)   It is important to understand the protective benefit of each helmet type, and to choose a helmet that best suits your riding style. And remember, a helmet works only when the chin strap is securely fastened, and act accordingly. Then, your helmet will protect you when you need it most. Institute for Traffic Accident Research and Data Analysis (ITARDA)