Why you should dismiss the CARRS-Q bicycle helmet research
Do Economic Benefits from Cycling Outweigh The Head Injuries Prevented By Helmets?
This is the fifth post in a series (Read Part One, Part Two, Part Three, Part Four) 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.
The CARRS-Q publication relies on a series of Victorian reports to find that:
“These reductions represented a considerable saving each year, for example a reduction of 40 severe head injuries (assuming $408,000 each) per year translated to savings of just over $16m per year.” (CARRS-Q, 2011, page 18)
Other researchers in other States have been critical of this series of reports. A West Australian study has found that:
“The magnitude of the decreases suggested by [the West Australian study] are below those found by Carr et al (1995) in Victoria [the fourth study discussed in Part Four]. Their findings were that the number of bicyclists hospitalised with a head injury had declined by 40% in the first four years of the helmet wearing legislation in Victoria. The findings of the present study suggested smaller reductions of between 11% and 21% in the number of bicyclists hospitalised with a head injury …”
“The study provided no clear answer as to whether the helmet wearing legislation had been an effective countermeasure in an economic sense …”
“In monetary terms, it is unlikely that the helmet wearing legislation would have achieved net savings of any sizeable magnitude. Under the assumptions used in the study, the most favourable estimate of the Net Present Value of the bicycle helmet legislation was $2.0 million, and this calculation excluded any costs associated with reduced cycling activity.” (Hendrie et al, Road Accident Prevention Research Unit, Department of Public Health, University of Western Australia: An economic evaluation of the mandatory bicycle helmet legislation in Western Australia, Insurance Commission of Western Australia Conference on Road Safety, 1999).
This West Australian study was not mentioned at all in the CARRS-Q publication.
The CARRS Q publication also reviews a huge number of reports all of which found clear economically significant social benefits for cycling. (CARRS-Q, 2011, Chapter 2)
These benefits are estimated to be between 40 cents per kilometre to NZ$2.14 per kilometre. (CARRS-Q, 2011, page 5)
In finding that head injuries economically outweigh other benefits, CARRS-Q also quoted a 2009 survey conducted for Sydney Metropolitan Cycle Network project, stating health benefits from cycling are only 1.42 cents per kilometre. (CARRS-Q, 2011, page 5)
However here is the actual cost analysis republished in the CARRS-Q publication (CARRS-Q, 2011, page 10):
Table 1. Estimated impact of cycling per bicycle kilometre travelled (Table 1 from PricewaterhouseCoopers, 2009).
|Type of impact||Benefit (2008 c/bicycle km)|
|Savings in user cost||16.39|
|Parking cost savings||1.00|
|Travel time costs||0.00|
|Bicycle crash cost||-2.03|
|Air pollution reduction||1.73|
|Greenhouse gas reduction||0.66|
|Total Net Benefit||48.22|
As can be seen from the actual figures, the total social economic benefit far outweighs the costs associated with cycling injuries.
The CARRS Q report also conceded that a Copenhagen study that controlled for (and therefore negated) factors such as age, gender, education, smoking status, cardiovascular conditions and body mass index still found that the benefits of cycling:
“… equated to a 40% lower chance of dying in a given year compared to non-cyclists.” (CARRS-Q, 2011, page 3)
Despite all of this, the CARRS-Q publication states that:
“… [other researchers] conclude that “the combined evidence presented in these studies [from countries without universal helmet legislation] indicates that the health benefits of bicycling far exceed the health risks from traffic injuries, contradicting the widespread misperception that bicycling is a dangerous activity … Our conclusion differs somewhat: cycling does have significant health benefits and therefore should be encouraged in ways that reduce the risk of the most serious of injuries … protection of the individual by simple and cost-effective methods such as bicycle helmets should also be part of an overall package of measures.” (CARRS-Q, 2011, page 10)
(Ed: we covered this strange conclusion by CARRS-Q in an earlier post)
Although a great body of research confirms there are significant health benefits to cycling, CARRS-Q position is that this research overstates the benefits because:
- Much of the work in this area has been carried out by “advocates.” (CARRS-Q, 2011, page 3)
- People who cycle more may be less likely to smoke and more likely to engage in other forms of physical activity. (CARRS-Q, 2011, page 3)
- People who are already healthy may be more likely to cycle. (CARRS-Q, 2011, page 3)
- Not enough people in Australia currently cycle long enough or often enough for there to be a significant health increase. (CARRS-Q, 2011, page 4)
- Costs relating to cycling crashes should be calculated not in terms of human capital, but in terms of willingness to pay. (CARRS-Q, 2011, page 7)
- The ‘safety in numbers’ effect will not be as effective if cyclists and pedestrians outnumber motor vehicles, because cyclists and pedestrians won’t know how to behave around motor vehicles. (CARRS-Q, 2011, page 8)
- Economic benefits don’t include health costs incurred from non-crash injuries from over-exertion, such as sprains and strains. (CARRS-Q, 2011, page 10)
CARRS-Q believes that the solution is to successfully encourage cycling while retaining helmet laws. This position denies the evidence that helmet laws reduce cycling.
In March 2012 the incumbent Queensland Government (responsible for commissioning the CARRS-Q publication) released an election commitment about cycling that states:
“Cyclists currently save the economy $63.9 million dollars per year in reduced congestion costs and $9.3 million in greenhouse gas emissions.” (On your bike: Getting more Queenslanders cycling, Queensland Labor Party, 2012, page 2)
This estimate of economic benefits, just for reduced congestion and greenhouse gas emissions not including personal health benefits, noise pollution or infrastructure provision, far outweighs the social health costs of head injury considered by CARRs-Q to be only $16 million per year. (CARRS-Q, 2011, page 18)
It is clear that the CARRS-Q publication fails to take a full account of all the social economic benefits of cycling in its assessment. It is also clear that CARRS-Q took an extremely conservative view of the proven health benefits of cycling, choosing to compare this to an overestimation of possible costs associated with cyclists’ head injuries. In this respect, the CARRS-Q publication fails to provide a proper, unbiased costs analysis of mandatory helmet laws.
The next post in this series will look at CARRS-Q’s claims that mandatory helmet laws do not discourage cycling. This position is fundamental to CARRS-Q’s claims about cyclists’ head injury rates (which CARRS-Q denies could be primarily caused by fewer cyclists), and CARRS-Q’s dismissal of the likelihood of significant social economic gains from increased cycling if the helmet laws were repealed.