Tuesday, May 10, 2011

The Negative Health Effects of Mandatory Helmet Laws

I did a research paper for a class on helmet laws. It is aimed at non-cyclists, and only looks at the public health issues surrounding the laws.

It seems to be common knowledge that wearing a helmet while biking is the smart, safe, necessary thing to do. Helmets are credited with reducing head injuries from cycling by 85 percent in the most optimistic study (Thompson, et al. 1471). With expected benefits of widespread helmet adoption so high, it is understandable that governments would be interested in legislation that makes helmets mandatory for bicyclists. But, despite the common assumption, mandatory helmet laws are not as effective or beneficial as they seem at first glance. Mandatory helmet laws should not be enacted because they are not the most effective way to reduce cycling deaths; additionally, they fail to differentiate between transport and sport cycling and therefore result in an undue burden on cyclists.

            There are some clarifications that must be made before one can discuss helmet laws in a meaningful way. The bicycle is a diverse vehicle, and there are necessary distinctions between uses and types of riding. The largest differences are between recreational and utility cycling.
Recreation cycling, also called sport cycling, encompasses the sport aspects of cycling and can be divided into road biking, mountain biking, and BMX. Each of these has very different associated risks associated with it. BMX emphasizes jumps and aerial tricks. Riders will often wear helmets with full facial protection, as well as leg and arm padding. Mountain biking does not involve jumps like BMX, but there are usually rocks, roots, and loose dirt that can make riding hazardous. Mountain biking helmets do not offer as much protection as BMX helmets, which is partly a response to the need for airflow because the more strenuous cardio that is a part of mountain biking. Road biking usually takes place on smooth clear roads, but involves much higher speeds than any other type of biking. Road helmets are similar to mountain biking helmets, but are usually more aerodynamic.
            Utility, or transport cycling is a mode of transportation, not recreation. It will often involve carrying some form of cargo, takes place in all types of weather, at all times of the year, and does not emphasize speed or adrenaline like most recreational riding. There are two strains within utility cycling: vehicular cycling and those who are described as “citizen cyclists” (Colville-Andersen, 2010). Vehicular cyclists emphasize the bike as a vehicle; they operate on roads as if they were driving a car. Acting like a car includes things such as riding in the center of the lane, not riding on sidewalks, and obeying all the traffic laws that apply to cars. Citizen cyclists are characterized by their similarity to pedestrians. They do not ride fast; they do not wear specialized clothing or gear.
            Because of the different requirements and conditions of different types of biking, laws that do not distinguish between them result in an unfair burden upon utility cyclists by requiring them to conform to standards set for very different types of activities. It is generally accepted by the biking community that helmet requirements ought to be different for sport cyclist and transport cyclists (FUB 1). The arguments in this paper focus on mandatory helmet laws that apply to utility cyclists; those that place restrictions on sport cyclists confront a sufficiently different set of considerations that they should discussed separately.
There is statistical support for differentiating between types of cycling. One study found that the accident rate for off-road trails, not inclusive of paved bike paths, was 53.73 percent, with a helmet usage rate of 43.71 percent. This is much higher than the accident rates for city surface streets and bike paths, which are 8.14 percent and 7.57 percent respectively, while helmet usage rates are 7.90 percent and 10.46 percent. The large differences shown by this data indicate that riding conditions vary greatly between transport cycling, which is almost exclusively on city streets and bike paths, compared to mountain biking (Rodgers 500).
            Studies that have looked at the effectiveness of helmets do not differentiate between types of cycling, in part because riders can shift between them at will. There have been many studies on the relationship between helmets and head injuries, but there data includes recreational riders ans well as utility cyclists. The most commonly cited study (Franklin 1) is from 1990, which showed that bicycle helmets reduce head injuries by 85 percent, and upper facial injuries by 95 percent (Thompson, et al. 1471).
Those numbers indicate that helmets are extremely effective, but there are large discrepancies between different studies on helmet effectiveness. Helmets have been shown to reduce head injuries by anywhere from 65 to 95 percent (Franklin 1). Some results for specific injuries are as low as 29 percent for concussions, or as high as 90 percent for fatalities (Franklin 1). Though there are contentions that studies have suffered from methodological problems that have magnified their helmets’ benefits (Franklin 2), it can generally be accepted that helmets do prevent head injuries in some cases.
A factor that must be considered when looking at the effectiveness of helmets concerns compensatory behavior. Some studies have shown that cyclist will engage in more risk taking behavior when they are wearing a helmet. A study by Gregory Rodgers concludes, “for the most part, those factors which increase the likelihood of accident are associated with increases in the likelihood of helmet use” (Rodgers 503). This means that the cyclists who wear helmets are more likely to be involved in an accident. Whether this is because bicyclists will wear helmets when engaging in riskier activity, or because they engage in riskier activity because they are wearing a helmet is not determined, but, “[t]he correspondence between higher accident risks and increases in helmet use also suggests that adult bicyclists are at least generally aware of the risks they face, and, on the whole, respond rationally to changes in the risk environment” (Rodgers 303). The self-regulation by cyclists helps to negate any benefits that a helmet law would have since the cyclists generally the most at risk already wear helmets.
Personal choices and behaviors complicate the issue of helmet laws on the level of the individual. When considering social health legislation, one must look at the effects of legislation on the population as a whole, not the effects upon specific individuals. At this level, mandatory helmet laws truly show their weakness. The goal of reducing cycling injuries is not achieved most effectively by mandatory helmet laws. They reduce the number of cyclists, and therefore make cycling more dangerous. Fewer cyclists make biking more abnormal, which lowers motorists’ awareness of bikes. The variable that has the greatest affect on cycling risk is motorist’s behavior (Jacobsen 209). When cyclists are ubiquitous, drivers expect there to be cyclists, drive accordingly, and are not caught off guard when there is a cyclist.
After introducing mandatory helmet laws, New Zeeland saw bicycle use decrease 22 percent, British Columbia saw a decrease of at least 28 percent, and Nova Scotia saw a decrease of at least 40 percent (Franklin 1). Others have recognized this trend. One study states that “the effect of legislation is to reduce bicycle riding by 20% to 40%” (De Jong 7). A reduction in cycling endangers cyclists because there is a clear inverse correlation between numbers of cyclists and risk of accidents. When there are more cyclists on the roads, motorists become more used to them being there, which leads to motorists driving in a way that accommodates bikes. Additionally, more bikes create a greater demand for bicycle infrastructure, which is safer than simply riding on roads designed solely for cars (Injury rates on paved bike paths are lower than injury rates on either urban roads or highways (Rodgers 500)) . Peter Jacobsen, in his study of the effect of numbers on walking and biking safety found that “data indicate[s] that decreasing bicycle riding leads to increased risk, and increasing risk leads to decreasing bicycle use”(Jacobsen 208). Helmet laws may increase helmet usage, but they will reduce the number of cyclists, which increases the risk of death.
As is shown in figure 1 (FUB 6), when helmet usage rates (port du casque), are compared with mode share (Part modale vélo), which is the percentage of total trips made by any mode of transportation that were made by bike, and deaths per billion km ridden (Tués/billion km). Deaths rates are highest in the U.S., where mode share is the lowest and helmet use the highest. The Netherlands has very low risk, with the lowest helmet rate and highest mode share. Despite some anomalies, there is a clear trend towards biking being safer in countries with high mode share. France and Denmark have the same helmet usage, but Denmark’s mode share is much higher, and their death rate is much lower. Jacobsen concludes, “Where, or when, more people walk or bicycle, the less likely any of them are to be injured by motorists. There is safety in numbers” (Jacobsen 209). Mandatory helmet laws could actually make cycling more dangerous by reducing the numbers of bicyclists.
There are clear drawbacks to helmet laws in relation to preventing death from accidents. Mandatory helmet laws can also be evaluated from the perspective of public health broadly, rather than just prevention of injury or death from accidents.  Here again, mandatory helmet laws fail to promote public health effectively. A study of the health impacts of mandatory helmet laws showed that a “net health benefit emerges only in dangerous bicycling environments under optimistic assumptions as to the efficacy of helmets” (De Jong 11). There are health benefits to the cyclists themselves, the reduced likelihood of injury to others, and reduced environmental impacts that result from people using bikes for transportation rather than cars. In fact, one researcher, Mayer Hillman, found that “even in the current hostile traffic environment, the benefits gained from regular cycling outweigh the loss of life years in cycling fatalities by a factor of around 20 to 1” (De Jong 7). He concluded that cycling should be promoted as a health benefit despite injury risks. In his words, “[f]ar from it being irresponsible…to encourage the general population to transfer from motorized transport to the bicycle whenever feasible, it could be considered irresponsible not to” (Hillman 986). Biking comes with many health benefits, which lower the risk of death from other factors, so that the danger of crashing is more than offset by the health benefits. An analogy to this situation could the fact that there almost no risk of every being in an accident of any sort if one never got off the couch but the benefits of being active so far outweigh any danger that no one in there right mind would attempt to convince someone that it is better for their health to never leave their couch. When the risks and benefits of cycling are looked at holistically, biking is overwhelmingly beneficial. Mandatory helmet laws could hurt public health because of the reduction they cause in cycling.
One obvious response to the data about mandatory helmet laws, would be to not mandate, but heavily promote helmet use. This issue is much more ambiguous than mandating helmet use, but it can have a similar negative effect. If helmet promotion portrays biking as a dangerous activity that requires a form of armor, or padding, it can hurt overall usage. Some will obviously ride who would not have ridden if helmets were mandatory, so the effects will be less, but the changes that it would bring in public perception could keep people from biking. There is not much data on the effects of helmet promotion, so a definitive position must be tentative. Any helmet promotion campaign would have to weigh the danger of exaggerating the need for helmets and keeping people from cycling. A campaign that emphasized the positive aspects of helmets increasing safety without portraying utility cycling as dangerous could be beneficial as long as it did not create the perception that biking is dangerous.
Mandatory helmet laws should not be enacted because they fail to achieve their goals of increased public health. Though helmets do reduce head injuries, they do not do so enough to offset the reduction in cycling rates that accompanies them being mandatory. Helmet laws endanger cyclists because there is a strong inverse correlation between mode share of bicycles and risk of death while biking. Additionally, the health benefits of cycling outweigh the risks, so any measure that reduces cycling rates will harm public health. In a perfect world, there would be high rates of helmet use and high mode share of bikes, but given the observed relationships, a high mode share of bikes with low helmet use is preferable to high helmet use and low bicycle use. Mandatory helmet laws make this preferred situation much less likely to occur, and therefore should not be supported on the basis of promoting public health.

Works Cited
Colville-Andersen, Mikael. "Sit Up Straight, Sydney." Copenhagenize. Ed. Mikael Colville-Andersen. N.p., 18 Mar. 2010. Web. 27 Apr. 2011.
De Jong, Piet. "The Health Impact of Mandatory Bicycle Helmet Laws." 4 Feb. (2010): 1-13. The Social Science Research Network. Web. 18 Apr. 2011.
Franklin, John. “Cycle Helmets: The Dilemma.” ECF AGM. May 2006. Web. 10 Apr. 2011.
"Généralisation du port du casque à vélo? Une fausse réponse à l’insécurité routière!" Fédération française des Usagers de la Bicyclette. Fédération française des Usagers de la Bicyclett, 2009. Web. 29 Apr. 2011.
Hillman, Mayer. "Cycling and Health." Letter. British Medical Journal 304.6832 11 Apr. (1992): 986-87. Web. 2 May 2011.
 Jacobson, Peter L. "Safety in Numbers: More Walkers and Bicyclists, Safer Walking and Bicycling." Injury Prevention 9.39 Feb. (2003): 205-09. Web. 18 Apr. 2011.
Rodgers, Gregory B. "Bicyclist Risks and Helmet Usage Patterns: An Analysis of Compensatory Behavior in a Risky Recreational Activity." Managerial and Decision Economics 17.05 Sept. (1996): 493-507. Web. 18 Apr. 2011.
Thompson, Diane C., Robert S. Thompson, Frederick P. Rivara, and Marsha E. Wolf. "A Case-Control Study of the Effectiveness of Bicycle Safety Helmets." New England Journal of Medecine 80.12 Dec. (1990): 1471-74. SocAbs. Web. 18 Apr. 2011.
Unwin, Nigel C. "Cycle Helmets—When is Legislation Justified?" Journal of Medical Ethics 22 Feb. (1996): 41-45. SocAbs. Web. 10 Apr. 2011.


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