Bicycle helmets to effective preventing head injury

Bicycle helmets have been proven to be effective in preventing head injury. Based on the research findings, it is possible to list the proven attributes required for an effective helmet design. The major research study supporting the factor is appended to the finding, often the attribute will have been mentioned in several studies.

• A helmet must be worn properly to be effective, Attewell et al (2001);


• Helmets are very effective in preventing skull fracture, but less effective in preventing brain injury, Henderson (1995).


• The helmet must remain on the head during the crash, Williams (1991);


• The helmet must remain in position during the crash, Williams (1991);


• The helmet must have the maximum possible coverage of the frontal and temporal areas of the head, Williams (1991), Cameron et al (1994) and McIntosh et al (1998);


• The helmet must have adequate energy attenuation characteristics, for a variety of impacted surfaces, including flat, blunt and sharp, Smith et al (1993);


• A drop energy requirement of between 1.5 and 2.2 metres appears to be adequate, Williams (1991) and Smith et al (1993);


• The criteria for the energy attenuation test should be in the region of 200g, McIntosh et al (1998);


• The helmet must retain its integrity during the impact, Ching et al (1997) and Williams (1991);


• The helmet must be retained, in case of a second impact, Williams (1991) and Smith et al (1993);


• A helmet with a hard shell appears to offer better protection from severe brain injuries, Rivara et al (1996);


• Severe brain injury occurs more often in impacts with other vehicles, McDermot et al (1993);


• The helmet for a young child needs to be different than for an older child or adult, Corner et al (1987).
  

Based on the review of the helmet effectiveness literature, there are several aspects of the helmet performance immediately before and during a crash, which need to be considered when reviewing the adequacy of a standard. These are grouped here into three requirements with a short explanation (with the related tests from the standard):

1. The helmet must be worn. A helmet must be worn to have any effect, must be attractive and comfortable for the wearer to be willing to wear it.

2. The helmet must remain in place during the crash. The retention system must be capable of keeping the helmet in place during the events immediately before (dynamic stability) and during (retention system strength) the crash.

3. The helmet must have adequate energy attenuation. The helmet must be capable of attenuating the impact to minimise injury. The helmet must cover the appropriate areas of the head; especially the frontal and temporal areas (test coverage). It must not disintegrate from the impact (helmet integrity) and must be capable of adequately minimising injury to the head resulting from impacts with different types of objects (energy attenuation and load distribution). The helmet must continue to remain in place on the head for a possible second impact (order of testing).