Change in Casualties to Cyclists Following The Helmets Law

Written in 1994

Introduction

The Federal Government took action in 1989 to make Australia the first country in the world to compel cyclists to wear helmets, but had little knowledge of the likely effects of its action. As the Government of Victoria told the Federal Parliamentary Committee that recommended compulsory helmets, “the incidence of bicycle helmet use has not yet reached a sufficiently high level anywhere in the world for a scientific examination of helmet effectiveness in injury reduction to be undertaken.” (1) Compulsory helmets therefore is an experiment with the safety of cyclists.

To be responsible, the Federal Government should at least have set up a system to monitor the effects of the helmet laws that resulted from its action. This would include measuring numbers of cyclists and casualties, in particular head injuries, pre-law and post-law. It did not, nor did any of the states or territories. The experiment is therefore uncontrolled.

Some states and territories have, however, made surveys to measure the effect of the helmet laws on helmet wearing. Incidental to this purpose, some of these surveys have measured changes in numbers of cyclists pre-law to post-law, with more or less accuracy, and in some places automatic counters have provided similar information. Wherever such surveys have been done, they have shown sharp declines in numbers of cyclists.

Established systems provide information on casualties to cyclists in the states and territories, but this information is not always in a form useful for making pre-law and post-law comparisons. Nor may it always be readily correlated with information on changes in numbers.

As the most reliable information from surveys is from New South Wales, the following analysis is for that state. It is expected that the conclusions would hold for the other states and territories.

Change in numbers of cyclists and casualties in NSW

After the helmets law was introduced in NSW in 1991, on 1 January for cyclists 16 and over and on 1 July for children under 16, the numbers killed in road traffic accidents declined: from 20 in 1990, to 10 in 1991 and 6 in 1992 (1). Government ministers claimed this as a measure of benefit of the law. The claim is here shown to be spurious.

With such small numbers, chance variations can be important; the respective numbers for 1993 and 1994 were 8 and 23. Also, account needs to be taken of the change in traffic conditions due to random breath testing etc and the post-law decline in the number of cyclists.

The effect of chance is small if casualties are measured as totals killed and seriously injured (admitted to hospital). For children aged 0-16, the group having the highest casualties as cyclists, these statistics from the Roads and Traffic Authority (RTA) (2) are as shown in Table 1.

TABLE 1

CHILDREN AGED 0-16 KILLED AND SERIOUSLY INJURED, NSW

Year Cyclists Pedestrians All road users

1989        175           380           1206
1990        152           354           1035
1991        115           315            877
1992         97           316            836
1993        103           281            829

The table is confined to ages 0-16, as there are no reliable data on the post-law decline in numbers of older cyclists.

To reduce chance variations, and being generous to ministers, we use the total of 1989+1990 as a measure of casualties pre-law, and 1992+1993 as post-law. On this basis, casualties declined from 327 pre-law to 200 post-law, or by 39 per cent.

How much of the decline can be explained by factors other than helmet wearing? First, improved traffic conditions due to such factors as random breath testing reduced casualties to all child road users by 25 per cent, as shown in Table 1, but, generous again, let us say it explains only the same decline in casualties to cyclists as to pedestrians, 19 per cent.

Second, the number of cyclists declined post-law. The RTA measured this decline for cyclists of estimated age under 16. A baseline survey in April 1991, pre-law for under 16s, counted cyclists passing chosen sites (3). In April 1992 and 1993, the RTA did similar surveys at the same sites (4,5). The number estimated to be under 16 declined from 6270 in 1991 to 3887 in 1992 and 3478 in 1993 – i.e. by 41 per cent on average. For 16 year-old cyclists, the helmets law came into effect on 1 January 1991, so that a decline in their numbers in response to the helmets law would have occurred before the April 1991 survey. It is here estimated as 41 per cent, the same as the under 16s, though it might well have been greater, teenage cyclists being the most averse to wearing helmets.

Combining the 19 and 41 per cent declines would explain a 48 per cent decline in casualties to 0-16 year-old cyclists, from 327 pre-law to 156 post-law. The actual number post-law was 200. Even based on the 41 per cent decline in number of cyclists alone, ignoring the effect of improved traffic conditions, 193 casualties would be expected, still below the actual number. Therefore, there is no evidence that the helmets law contributed to the decline in casualties, except by discouraging cycling. The remaining cyclists actually suffered more casualties in proportion to their numbers.

One possible explanation for the increased rate of casualty is that helmeted cyclists feel protected and therefore ride less carefully than before. Elliott and Shanahan Research, in a 1986 study of young people’s attitudes to helmet wearing (6), found that they “believe that approved helmets would save their heads and lives in the event of a serious accident (with a bus or truck).” Such a belief is likely to have been reinforced by propaganda promoting helmet laws.

A second explanation could be that motorists seeing fewer cyclists on the roads give less thought to them.

Third, the mass of a helmet increases forces on the head when a cyclist encounters bumps, and may result in loss of balance.

Numbers for head injury are not published, but in a pamphlet entitled “The current state of bicycle riding”, June 1994, the Road Traffic Authority of NSW claimed that “NSW data show a strong relationship between reductions in head injury rates and increasing helmet wearing rates”, and “a substantially larger decrease in bicycle head injuries than other types of injuries”. Upon request, the RTA provided the numbers, which they had obtained from the Department of Health, as follows.

TABLE 2

HOSPITAL SEPARATIONS FOR NSW BICYCLISTS 1988/89-1992/93

 Year <16 head >16 head <16 other >16 other

1988/89        414        238        908        497
1989/90        453        274       1053        642
1990/91        384        209        926        540
1991/92        272        176        815        508
1992/93        273        170        893        584

From 384 in 1990/91, the latest pre-law year, the number of head injuries to cyclists less than 16 years old declined to 272 in 1991/92, or by 29 per cent, which is less than the decline in the number of cyclists – 38 per cent. This means that the risk of head injury for the remaining cyclists increased following the law. Even comparing the two years before the helmets law, 1989/90 plus 1990/91, thereby including the highest pre-law number, with the two post-law years 1991/92 plus 1992/93, the decline in head injuries, 35 per cent, is stll less than the 41 per cent decline in numbers of cyclists and compares with the 48 per cent decline that could be expected if the improved traffic conditions were also taken into account. The RTA’s point that head injuries declined more than other types of injuries is of little comfort here.

It should be noted that the numbers from NSW Health in Table 2 are much higher than those in Table 1 from the RTA of NSW. NSW Health has advised that one reason for the difference is that their statistics include patients who may not have been insured or have been involved in an accident serious enough to warrant the attendance of the police. They also confirmed that it was “highly likely” that their statistics include most of the RTA’s category “Other injured”, who suffered less severe injuries than the “Seriously injured”. Consequently, many of the head injuries included in Table 2 would have been of a superficial kind.

Conclusion

Total injuries and head injuries to cyclists under 16 in New South Wales declined following the introduction of the compulsory helmet- wearing law. But the law had the important effect of discouraging cycling.

Pre-law to post-law, both total injuries and head injuries declined less in proportion than the decline in the number of cyclists. Even without allowing for improved traffic conditions, for the remaining cyclists the risk of injury including head injury therefore increased.

References

1. Submission by the Government of Victoria to the House of Representatives Standing Committee on Transport Safety: motorcycle and bicycle helmet safety inquiry, 1985

2. Roads and Traffic Authority of NSW, Road Traffic Accidents in NSW Statistical Statement, annual, 1989-1993

3. Walker, M.B., Consultant report CR 1/91 for Roads and Traffic Authority of NSW, Road Safety Bureau, Law compliance and helmet use among cyclists in New South Wales, April 1991, Sydney, July 1991

4. Walker, M.B., Law compliance among cyclists in New south Wales, April 1992, A third survey, published by Roads and Traffic Authority of NSW, Network Efficiency Branch, Sydney, July 1992

5. Smith, N.C. and Milthorpe, F.W., An observational survey of law compliance and helmet wearing by bicyclists in New South Wales – 1993, published by Roads and Traffic Authority of NSW, Transport and Network Development Branch, Sydney, September 1993.

6. Elliott and Shanahan Research, An exploratory study of high school students’ reactions to bicycle helmets, The Road Traffic Authority of Victoria, Melbourne, April 1986.

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