Why you should dismiss the CARRS-Q bicycle helmet research
Do Helmet Laws Discourage Cycling?
This is the sixth post in a series (Read Part One, Part Two, Part Three, Part Four, Part Five) looking at the non-peer reviewed CARRS-Q publication entitled “Bicycle Helmet Research“, published in 2011 and widely relied upon to support mandatory helmet laws for cyclists. This publication was commissioned by the State Government to support its policy of mandatory helmet laws in Queensland, Australia, in the face of criticisms of its lack of support for Brisbane’s public bike hire scheme.
Two key findings of the CARRS-Q publication are that mandatory helmet laws:
“discouraged people from cycling twenty years ago when it was first introduced … [however] there is little evidence that it continues to discourage cycling.” (CARRS-Q, 2011, page 53)
“ … there is little evidence that there is a large body of people who would take up cycling if the legislation was changed.” (CARRS-Q, 2011, page 53)
The CARRS-Q publication doesn’t address the fact that only two bicycle hire schemes in the world are failing, in Brisbane and Melbourne both where helmet use is mandatory; or that the CEO of one of those schemes admits there’s no doubt mandatory helmet laws are affecting the scheme.
While the above effects on bike hire schemes are not research based, CARRS-Q also doesn’t address the continuing decline in Australian children riding to school or anywhere else. Australian modal share of cycling has only gone from 1.1% in 2000 to 1.5% in 2009. (Australian Bicycle Council, National Cycling Strategy 2011 – 2016, page 14)
The CARRS-Q publication says that:
“[c]ensus data from South East Queensland suggests that the number of journeys to work by bicycle fell after the introduction of helmet legislation … although the most recent available data suggests the absolute numbers now exceeds pre-legislation trip numbers. Measured as a proportion of mode share, bicycle trips to work have fallen from 1.6% pre-legislation … to 1.1% post-legislation.” (CARRS-Q, 2011, page 20)
So, after 20 years, the best that CARRS-Q can claim is that “absolute numbers” of cycling rates in South East Queensland now exceed what they were immediately before helmet laws were introduced.
The population of South East Queensland before helmet laws were introduced was 2.83 million. It is now 4.51 million, an increase of over 66%. The only conclusion to draw from this 20 year stagnation of absolute cycling numbers is that, around about the time of helmet laws being introduced, something happened that severely curtailed cycling in Australia.
The CARRS-Q publication also relies on Melbourne research that:
“ … demonstrated a doubling in the use of bicycles by adults in metropolitan Melbourne. However, there was a decrease in the use of bicycles by children. A decrease in cycling exposure of 10% was observed in children (5-11 years) and an even larger decrease of 44% for teenagers (12-17).” (CARRS-Q, 2011, page 20)
What this Melbourne research actually found was that there was a significant decrease in the numbers of children and teenage cyclists as a result of helmet laws. As discussed in a previous post, the Melbourne study also noted a possible increase in adult cyclists but recognised that this was difficult to confirm as the there was 4 years between the two surveys relied upon for ascertaining the number of adult cyclists. The first survey was conducted in 1987/88, about three years before helmet laws were introduced.
The CARRS-Q publication also relies on data from Melbourne, Perth and Sydney that shows that cycling rates have increased over the last 5 years. Given that helmet laws were introduced 20 years ago in these cities, and rates have only increased in the last 5 years, it is difficult to draw any correlations between these recent increases and the effect of helmet laws.
During the regime of mandatory helmet laws, an entire generation has attained an age historically popular for cycling. Australians under the age of 25 cannot remember a time when helmets were not mandatory. It is extremely dubious to rely on these recent increases as evidence that helmet laws do not affect cycling rates. However this is exactly what the CARRS-Q publication does.
The CARRS-Q publication concludes that:
“It is reasonably clear that [helmet laws] discouraged people from cycling twenty years ago when it was first introduced. Having been in place for that length of time in Queensland and throughout most of Australia, there is little evidence that it continues to discourage cycling.” (CARRS-Q, 2011, page 53)
One can only assume that CARRS-Q is referring to some type of evidence other than the woeful cycling rates mentioned above. Some kind of research specifically asking would-be cyclists whether mandatory helmet laws are the cause of their choice not to cycle. Recent Sydney-based research addresses exactly this question, and identifies that 23.6% of adults would cycle more often if they didn’t have to wear a helmet. (Rissel et al: The possible effect on frequency of cycling if mandatory bicycle helmet legislation was repealed in Sydney, Australia: a cross sectional survey, Health Promotion Journal of Australia, page 181)
Of specific interest is the Sydney report’s findings that mandatory helmet laws discourage 19% of non-cyclists from any type of cycling. In other words, here is research that shows that existing cyclists would ride more often, and non-cyclists would start riding, if helmet laws were repealed.
It should be noted that, while criticism can be made of this study on the grounds that the questions were too subjective, the results are in accord with ABS Census data:
Percentage of trips made to place of employment by bicycle before and after introduction of mandatory helmet laws: Queensland
(Source: Summary of Characteristics of Persons and Dwellings Queensland, census data collected 1981, 1986, 1991, 1996, 2001 and 2006, Australian Bureau of Statistics.)
Recent New Zealand research also confirms these findings, finding that regular cyclists ride half as often as they did prior to mandatory helmet laws.
(Clarke: Evaluation of New Zealand’s bicycle helmet law, New Zealand Medical Journal, 2012)
CARRS-Q has ignored significant research showing that helmet laws are directly responsible for significant reductions in cycling. This position removes all credibility the CARRS-Q publication has in comparing the social economic benefits of cycling, including health, traffic congestion, pollution and infrastructure, to the possible costs associated with head injuries if mandatory helmet laws were repealed.
The last post in this series will look at CARRS-Q’s use of existing police and hospital data and available bicycle fatality data. While CARRS-Q relies on this data to support its stance in favour of mandatory helmet laws, it is clear that the data is unreliable and that CARRS-Q utilises a number of very dubious assumptions to reach its conclusions.