Testing of Production Prototypes of a self-protective Headband for Car Occupants

This publication is the third in a series of reports for the ATSB in which we have detailed the development of a protective headband for car occupants. In CR193, we documented the results of tests made to determine the energy absorbing characteristics of several candidate materials. CR205 reported further investigations of possible production grade materials and discussed aspects of the design that would determine the general form of the headband in a consumer version of the product.

This report details the results of tests made on the headband, which may be compared with the requirements of the United States Federal Motor Vehicle Safety Standard 201. That standard requires a certain level of head protection for the occupants of the vehicle from the upper interior of the car. The standard stipulates that a free motion headform be launched against the interior components of the car at a speed of up to 24 km/h. The requirement in these tests is that a modified value of the Head Injury Criterion, HIC(d), be less than 1000. The nature of the test required by FMVSS 201 provides a method by which the effectiveness of the headband may be assessed.

In this study, prototype headbands were fabricated according to a design developed in CR205. The energy absorbing element was machined from a solid block of expanded polypropylene and sandwiched between a styrene outer shell and a cloth liner. These prototypes were designed to be dimensionally and materially similar to a future consumer version of the product (should such a version arise).

The aim of the testing was to choose structures that would behave similarly to structures found in the interior of a car. The test structure was designed so that the impact stiffness could be varied. The structure was such that a straightforward execution of the test procedure (without the headband) produced HIC(d) results that ranged from a pass (717), to a moderate fail (1623). The tests were then repeated with a headband attached to the headform so that a comparison of impacts with and without the headband could be made.

Two grades of EPP were evaluated in this study; a 50 g/l density foam and a 70 g/l density foam. The tests showed that headbands manufactured from either grade of EPP provided substantial protection with the most severe impact producing a HIC(d) value of 601 (compared to 1623 for the bare headform in the same test). Further analysis of the dynamic crush characteristics of the headband showed that the 70 g/l EPP was a more efficient energy absorber than the lower density material. This was also reflected in lower HIC(d) values in tests that used the 70 g/l foam. The headband provided protection by limiting peak loads and absorbing significant amounts of energy.

In frontal impacts, the headband would provided significant head protection for car occupants. This would be particularly beneficial for the occupants of older vehicles. Parts of Australia have a median vehicle age around 10 years. That implies that, on current trends, it will take 10 years before a new vehicle safety feature, introduced today, will be present in half the car fleet in this country. The headband may provide the drivers of older cars some of the benefits of new safety features immediately. We expect that there would also be benefits for the occupants of newer cars, as the headband would provide protection from striking objects that are not protected by padding or airbags.

Road attitudes towards speed of car enforcement

A clear majority of people (56%) agreed that there is too much of a focus on speed in television commercials for new cars. Community support for this view was unusually emphatic, with 41% of people indicating that they agreed strongly with the proposition. By contrast, only 17% of respondents said they disagreed strongly.

This pattern of response was consistent across States and types of location, but did vary somewhat by sex and age. The belief that speed is over-emphasised was more prevalent among females (61%, compared with 51% of males) and people aged 40 years or over (69%, compared with 43% of younger people).

Overall, 40% of the community supported an increase in the number of speed cameras, 42% supported an increase in speed limit enforcement and 23% supported an increase in the severity of speeding penalties. Relatively few people favoured a reduction in any of these items.

Residents from NSW were more supportive of increases in speed cameras (48%), speed limit enforcement (46%) and penalties (27%) than were residents from the other four States. People from South Australia and Western Australia were least likely to support increases in speed cameras (26% and 31% respectively) and speed limit enforcement (31% and 38%). This finding is perhaps not surprising for Western Australian residents, given that they were much more likely to have been booked for speeding than drivers elsewhere (30% versus the national average of 19%).

Potential Benefits and expenses of Speed Changes on Rural Roads

The objective of the project was to explore the potential economic costs and benefits of changes to speed limits on rural roads in Australia. Net costs and benefits were estimated over a range of mean travel speeds (80 to 130 km/h) for the following road classes:

• freeway standard rural roads (dual carriageway roads with grade-separated intersections and a design speed of 130 km/h, usually designed as such when originally constructed


• other divided rural roads (not of freeway standard)


• two-lane undivided rural roads (two illustrative ‘road stereotypes’ with different crash rates).


Specific objectives were to explore a number of scenarios, such as:


• increasing limits on high standard roads with a low crash rate (per vehicle-kilometre) from 110 to 130 km/h (or intermediate speeds)


• increasing limits on high standard roads with a low crash rate from 110 to 130 km/h subject to a variable speed limit system that would reduce speeds under adverse conditions such as poor light, bad weather or dense traffic (‘VSL option’)


• decreasing limits on lower standard rural roads with higher crash rates.
  

Assessing the level of safety provided by the Snell B95 standard for bicycle helmets

Changes have been made to the Trade Practices Act intended to legalise the sale in Australia of bicycle helmets meeting the American Snell B95 Standard. These changes have been made as part of the regular review of the mandatory consumer product safety standard for pedal cyclists under the Trade Practices Act 1974 as the current regulation, which was based on AS 2063.2- 1990 and had become outdated, Department of the Treasury (1999). The State and Territory road authorities have not accepted the changes. Specifically, the road authorities have expressed concern regarding two areas:

• The lack of a quality assurance process for Snell-certified helmets on the Australian market; and,


• Whether the technical differences between the Snell B95 and AS/NZS2063 standards reflect significant differences in the level of safety provided by helmets to these two standards.
  

The aim of this project was to assess whether the differences between the technical requirements and quality assurance approaches used by the Snell B95 and AS/NZS 2063:1996 standards for bicycle helmets are likely to result in significant differences in the level of safety provided to the user. This was done by:

• Reviewing existing studies of bicycle helmet effectiveness;


• Testing representative samples of helmets to both standards; and,


• Considering the role of the quality assurance regime within the manufacturing process, and the need for some form of external quality assurance process conducted by independent testing laboratories.
  

The Snell Memorial Foundation is a not-for profit organization, which tests and certifies various kinds of helmets for use in specific activities. Snell uses a two-part process consisting of:

Certification Testing – The manufacturer submits sample helmets to Snell, which are subjected to the testing required by the Standard at a Snell laboratory. The helmet receives certification when these tests are completed successfully.

Random Sample Testing – The Foundation acquires samples directly from consumer sources such as retail outlets. The helmets are inspected and tested in the Snell laboratory to the requirements of the Snell standard.

In the USA the CPSC Regulation for Bicycle Helmets became law in 1998. The manufacturer or importer self certifies the helmet to the Regulation. As part of the certification the manufacturer is required to keep full records for three years of a 'reasonable test program' in support of the certification and these must be available on call.

For a helmet to be certified to the AS/NZS 2036-1996 standard, it must pass the following set of requirements:

• Manufacturers Quality Plan audit by SAI-Global.


• Type Testing of samples of the production helmets by an accredited laboratory to the requirements of the standard. From this point the design of the helmet is frozen, any changes require a re-certification.


• Batch Release Testing, as production precedes each batch of the product is kept under bond and are not released for sale until a specified number of samples are tested.
  

The effectiveness of the bicycle helmet quality system currently in use in Australia is demonstrated by only one public recall of bicycle helmets (in 1998) occurring in the last five years, of a relatively small number of helmets. In the USA in the same time span 8 public recalls of a total of 331,900 helmets have been made. Recalls are relatively ineffective for maintaining safety of personal equipment, as it is difficult to get the publicity to the user effectively. The Snell Memorial Foundation has never successfully initiated and completed a recall against its range of voluntary standards.