Alan @ EcoVelo points me to a study recently published in the journal Injury Prevention showing that provincial helmet laws have no impact on bicycle ridership in Canada.
One of the more common arguments against mandatory helmet laws used by I and others is that mandatory helmet laws discourage bicycle riding. This Canadian study, however, compares cyclist mode share between 2001 and 2007 in the two provinces that implemented mandatory helmet laws versus the other six that didn’t and saw no difference.
I interviewed one of the study authors, Jessica Dennis. She completed her MSc in epidemiology at the University of Ottawa.
Do you and the other researchers have a personal interest in the topic? Are you cyclists? And do you wear helmets?
Two of us are cyclists and yes, we always wear helmets! I’ve been in a few collisions during my bicycling career – enough to make me never want to ride without a helmet. I became interested in this project when I came across an article arguing that mandatory helmet laws would discourage people from bicycling. I was so surprised at how often this argument was used, despite little evidence to this effect, that I decided to get involved.
Your research shows helmet use is higher for children when helmet legislation applies to all ages vs only children. Do you have any thoughts on why this might be?
As we hypothesize in our article, this could be because fewer adults are role-modeling this behaviour. A 2005 study of bicyclists in Toronto, Canada found that 95% of children riding with a helmeted adult wore helmets, compared to 41% of children riding with a non-helmeted adult (Khambalia et al. 2005). Enforcing a helmet law that only applies to youth could also be more difficult than enforcing a helmet law that applies to all cyclists. I imagine it would be hard for a police officer to distinguish a non-helmeted 16 year old cyclist who should be ticketed from a non-helmeted 19 year old cyclist who is exempt from the law.
(Khambalia A, MacArthur C, Parkin PC. Peer and adult companion helmet use is associated with bicycle helmet use by children. Pediatrics. 2005 Oct;116(4):939-42.)
Do you believe your research is reproducible in the United States? Would a similar study in the US have similar results?
I would love to see similar research conducted in the United States. A 1999 study in 3 NY City suburbs found results similar to ours in that they found that helmet use increased as more people were targeted by legislation (Puder et al, 1999). I think looking at this question on a larger scale would help us to better understand the benefits of helmet laws that apply to all cyclists.
Although bicycling culture differs from one country to another, I think the US and Canada are more alike than say, the US and the Netherlands. I think it’s reasonable to think that if helmet laws didn’t stop Canadians from cycling, then they won’t stop Americans from using their bicycles either.
(Puder DR, Visintainer P, Spitzer D, Casal D. A comparison of the effect of different bicycle helmet laws in 3 New York City suburbs. Am J Public Health. 1999 Nov;89(11):1736-8.)
You are undoubtedly aware of the Australian experience [D. L. Robinson 1996] and an earlier Novia Scotia study [LeBlanc, Beattie & Culligan 2002]. Why does your meta-analysis draw different results? Are there other similar studies with results that match yours?
First of all, I often see the Nova Scotia study used as evidence that helmet laws discourage bicycle use. However this study was not designed to measure bicycle use so this conclusion absolutely cannot be drawn from this data. In fact, no conclusion on bicycle use can be drawn from this data. As LeBlanc (the study author) responds in a letter,
“The variations in collection methods are a far more plausible explanation for the variation in cycling rates and proportion of child cyclists than the legislation.” (LeBlanc, 2002)
We found that helmet laws did not cause people to abandon their bicycles. This is in line with a 2001 study by researchers in Toronto, Canada who found that introducing a child helmet law didn’t affect bicycle use among children 5-14 years of age (Macpherson et al. 2001).
I am aware of the Australian studies cited by D.L. Robinson. One of the big differences between the Canadian studies and the Australian studies is that the Australian studies only looked at bicycle use in the two years immediately following the introduction of legislation.
It’s unclear if the drop in bicycle riders was sustained or if it was a short-term effect of the legislation, or even if it was due to differences in how the study was carried out from one year to the other. The Canadian studies look at bicycle use in the several years following legislation, which gives a better overall picture of long-term trends in bicycle use.
(LeBlanc, J.C. Butting heads over bicycle helmets (author reply). CMAJ. 2002 Aug 20;167(4):338-9.
Macpherson AK, Parkin PC, To TM. Mandatory helmet legislation and children’s exposure to cycling. Inj Prev. 2001 Sep;7(3):228-30.)
Between 2001 and 2007 (your study period), bicycle use has exploded all over North America. Against this background, how do you measure if helmet laws inhibited bike use or not?
Our study looked at bicycle use before and after helmet laws were implemented in two Provinces. In addition, we looked at bicycle use over the same time period in the remaining eight Canadian Provinces. This is a major strength of our study. When we compared biking trends in the provinces that changed their helmet laws to the biking trends in provinces that didn’t change their helmet laws, we saw no difference. This tells us that helmet laws didn’t have an effect on whether or not people used their bicycles.
What is your opinion on police enforcement of bicycle helmet laws? Should police spend their resources on targeted enforcement of bike safety laws, such as helmet and other bike equipment laws?
Helmet laws are not meant to divert valuable police resources away from fighting crime. To me, the biggest benefit of helmet laws is that it normalizes helmet use. Most people are law-abiding citizens, and when a law is in place, they will try to obey it, regardless of whether or not a policeman is standing over their shoulder. The goal of helmet laws is to change bicycling culture, so that people don’t think twice about putting on a helmet – it will just be an accepted piece of bike gear, the same way that everyone buckles their seatbelts when riding in a car.
Thank you to Ms Dennis for her willingness to interact on this. This study will likely prompt a lot of discussion, but please keep it civil.