Protective Performance of Bicycle Helmets introduced at the same time as the Bicycle Helmet Wearing Law in Victoria

Monash University Accident Research Centre - Report #59 - 1994

Authors: M. Cameron, C. Finch & P. Vulcan

Full report in .pdf format [2.6MB]

Abstract:

This project aimed to examine any changes in helmet performance due to the amendment of the Australian Standard for bicycle helmets, which was made at essentially the same time as the introduction of the bicycle helmet wearing law in Victoria on 1 July 1990. There was concern that the deletion of the penetration test from the Standard may have resulted in reduced protection to the heads of cyclists involved in crashes. Forty helmets sustaining impacts in crashes were collected from cyclists who were killed or treated at selected Melbourne hospitals during 1991-92. These helmets were predominantly "foam-only" (a foam helmet often with a material cover), "micro-shell" (a foam helmet with a thin plastic shell), or light weight "hard-shell" (a foam helmet with a hard plastic shell) allowed under the amended Standard. The new helmets were tested, and information on the bicyclists' injuries obtained, so that comparison could be made with similar information previously obtained for older-design, heavier hard-shell helmets. It was concluded that the new helmets transmit a lower level of peak acceleration to the cyclist's head inside the helmet, for a given severity of impact on the external surface of the helmet. There was no evidence of a real difference in protective performance between the older and new helmets so far as actual head injury risks are concerned. This may have been due to the absence of a difference or due to the relatively small number of helmets considered in the two helmet groups.

Executive Summary

This project was commissioned by VicRoads to examine any changes in helmet performance due to the amendment of the Australian Standard for bicycle helmets, which was made at essentially the same time as the introduction of the bicycle helmet wearing law in Victoria on 1 July 1990. There was concern that the deletion of the penetration test from the Standard may have resulted in reduced protection to the heads of cyclists involved in crashes.

The Royal Australasian College of Surgeons (RACS) had collected 64 helmets which had sustained an impact in a crash which resulted in the helmet wearer being admitted to or treated at hospital during 1987-89. These helmets were predominantly heavy weight hard-shell type. The helmets were submitted to the testing laboratory of Technisearch Limited, who simulated the principal helmet damage by impact tests on new helmets of the same make, model and size. The test results included the drop height (a measure of the impact severity) and the peak acceleration of the headform inside the helmet. Information on head injuries was also obtained.

Forty helmets sustaining impacts in crashes were collected from cyclists who were killed or treated at selected Melbourne hospitals during 1991-92. These helmets were predominantly "foam-only" (a foam helmet often with a material cover), "micro-shell" (a foam helmet with a thin plastic shell), or light weight "hard-shell" (a foam helmet with a hard plastic shell) allowed under the amended Standard. The new helmets were also tested by Technisearch, and information on the bicyclists' injuries obtained, so that comparison could be made with the information obtained by the RACS.

The conclusions regarding the protective performance of the new helmets, in comparison with the older design, heavier hard-shell helmets, were:

  1. The new helmets transmit a lower level of peak acceleration to the cyclist's head inside the helmet, for a given severity of impact on the external surface of the helmet, for a range of impact types representative of those occurring in real bicycle crashes (the majority resulting in blunt impacts to the helmets).
  2. There was no evidence of a real difference in protective performance between the older and new helmets so far as actual head injury risks are concerned. This may have been due to the absence of a difference or due to the relatively small number of helmets considered in the two helmet groups.

It was also concluded that the specified drop height of 1500 mm for the impact energy attenuation test in the Australian Standard has been set too low if the intention is to cover closer to the full range of impact severities experienced by the helmets of cyclists involved in crashes resulting in severe injury. In addition, since one-third of the major impacts on the new helmets occurred below the test line, consideration could be given to lowering the line to ensure that helmets provide protection against a larger proportion of impacts sustained in real crashes.

Sponsor: Roads Corporation (VicRoads)