Bicycle helmet

A bicycle helmet is a helmet intended to be worn while riding a bicycle. They are designed to attenuate impacts to the head of a cyclist in falls while minimizing side effects such as interference with peripheral vision.^[1] There is intense academic debate on whether helmet use offers any reduction of the chance of head injury. The debate on whether helmet use should be compulsory is even more intense and occasionally bitter, often based not only on differing interpretations of the academic literature, but also on differing assumptions and interests on the two sides. Image File history File links Metadata Size of this preview: 754 × 599 pixelsFull resolution (800 × 636 pixel, file size: 78 KB, MIME type: image/jpeg) Bicycle Helmet (Cykelhjelm) Photo taken, Jørgen Larsen, 2006-07-13 File history Legend: (cur) = this is the current file, (del) = delete this old version... Image File history File links Metadata Size of this preview: 754 × 599 pixelsFull resolution (800 × 636 pixel, file size: 78 KB, MIME type: image/jpeg) Bicycle Helmet (Cykelhjelm) Photo taken, Jørgen Larsen, 2006-07-13 File history Legend: (cur) = this is the current file, (del) = delete this old version... A person wearing a helmet. ... For other uses, see Bicycle (disambiguation). ... A cyclist is a person who engages in cycling whether as a sport or rides a bicycle for recreation or transportation. ...

A cycle helmet should be light in weight and should provide adequate ventilation, because cycling can be an intense aerobic activity which significantly raises body temperature and the head in particular needs to be able to regulate its temperature. Aerobic exercise refers to exercise that is of moderate intensity, undertaken for a long duration. ...

About helmets

Standards

In the United States the Snell Memorial Foundation, an organization initially established to create standards for motorcycle and auto-racing helmets, implemented one of the first standards. The American National Standards Institute (ANSI) created a standard called ANSI Z80.4 in 1984. Later, the United States Consumer Product Safety Commission (CPSC) created its own mandatory standard for all bicycle helmets sold in the United States, which took effect in March 1999. Shortcut: WP:-( Vandalism is indisputable bad-faith addition, deletion, or change to content, made in a deliberate attempt to compromise the integrity of the encyclopedia. ... Shortcut: WP:-( Vandalism is indisputable bad-faith addition, deletion, or change to content, made in a deliberate attempt to compromise the integrity of the encyclopedia. ... Started in 1957, the Snell Memorial Foundation is a not-for-profit organization that was created to provide a high quality standard of safety for helmets. ... The American National Standards Institute or ANSI (pronounced an-see) is a nonprofit organization that oversees the development of standards for products, services, processes and systems in the United States. ... This article is about the year. ... The Consumer Product Safety Commission (CPSC) is an independent agency of the U.S. federal government created in 1972 through the Consumer Safety Act to protect “against unreasonable risks of injuries associated with consumer products”. As of 2006 its acting chairman is Nancy Nord, a Republican. ... March is the third month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days. ... This article is about the year. ...

In the European Union (EU) the currently applicable standard is EN 1078:1997.

In the UK the current standard is BS EN 1078:1997, which is identical to the EU standard, and which replaced BS 6863:1989 in 1997.^[2]

The CPSC and EN1078 standards are lower than the Snell B95 (and B90) standard; Snell helmet standards are externally verified, with each helmet traceable by unique serial number. EN 1078 is also externally validated, but lacks Snell's traceability. The most common standard in the US, CPSC, is self-certified by the manufacturers. It is generally true to say that Snell standards are more exacting than other standards, and most helmets on sale these days will not meet them (no current Bell brand helmet is Snell certified, some Specialized ones are – the Snell Memorial Foundation website includes a list of certified helmets).

In 1990 the Consumers' Association (UK) market survey showed that around 90% of helmets on sale were Snell B90 certified. By their 1998 survey the number of Snell certified helmets was around zero. Hard shells declined rapidly among the general cyclist population over this period, almost disappearing by the end of the decade, but remained more popular with BMX riders as well as inline skaters and skateboarders. Which?, until September 2004 known also as the Consumers Association, is a consumer rights organisation in the UK, founded in 1957 by Michael Young. ... A BMX Race. ...

Although helmet standards have weakened over time^[3] there is no data on which to base an assessment of how this has affected the design goal of mitigating minor injuries. Minor injuries are substantially under-reported and it is difficult if not impossible to effectively measure such injuries on a meaningful scale.

A helmet's ability to absorb energy could be improved by increasing the volume of polystyrene, but this would make it thicker, heavier, and hotter to wear. The trend is towards thinner helmets with many large vents. This trend to lower standards has been noted in some of the studies^[4] It is relatively common for helmets to fail on test, and some helmets on sale are not certified to any accepted standard.^[5] The most widely-cited pro-helmet studies were conducted when most helmets were of a hard-shell construction; these are now rare outside of niche applications such as BMX.

Most of the standards are designed to be passable using current designs and materials rather than to set a certain minimum safety standard. Tests typically involve weighting the helmets and dropping them onto anvils with flat, hemispherical and cornered (comparable to a kerbstone) shapes.^[5] Since the hemispherical and cornered anvils present the most difficult tests to pass, they are tested with a shorter drop, although there is no reason in practical riding why a person falling onto a flat surface would not fall as far as someone hitting a round object. A sphere is a symmetrical geometrical object. ... A Kerb ITS Curb lozl may be: the side of a road; see curb (road). ...

Design and materials

There are two main types of helmet: hard shell and soft/micro shell (no-shell helmets are now rare). In both types impact energy is absorbed as a stiff foam liner is crushed, up to the point where the liner is crushed to its minimum thickness, or the helmet shatters, after which no further energy is absorbed. Collision energy varies with the square of impact speed: a typical helmet will absorb the energy of a fall from a bicycle, an impact speed of around 12mph or 20 km/h. It will only reduce the energy of a 30 mph or 50 km/h impact to 27.5 mph or 45 km/h, and even this will be compromised if the helmet fails. This energy calculation is based on the standards, which take no account of the weight of the rider's body, which may be a factor in headfirst falls. This article does not cite any references or sources. ...

As a subsidiary effect they also spread point impacts over a wider area of the skull. Hard shell helmets do this better, but are heavier and less well ventilated. They are more common among stunt riders than road riders or mountain bikers. Additionally, the helmet will reduce superficial injuries to the scalp. Hard shell helmets can also reduce the likelihood of penetrating impacts although these are very rare. A BMX Race. ... A road bicycle is a bicycle designed for use on roads, as opposed to rough terrain. ... Mountain biker riding in the Arizona desert. ...

The key component of most modern bicycle helmets is a layer of expanded polystyrene (EPS), essentially the plastic foam material used to make inexpensive picnic coolers. This material is sacrificed in an accident, being crushed as it absorbs a major impact. Bicycle helmets should always be discarded after any accident. Polystyrene (IPA: ) is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. ... Sea foam on the beach Foam on a cappuccino Fire-retardant, foamed plastic being used as a temporary dam for firestop mortar in a cable penetration in a pulp and paper mill on Vancouver Island, British Columbia, Canada. ...

Helmets are most effective in straight line, or linear, blows to the head at moderate speed. Helmets are not well designed to deal with high speed impacts or rotational stresses (crashes that are not centred, and involve rotation of the head). They are not designed to provide adequate protection for a collision involving another moving vehicle, (e.g. a car).

A common misunderstanding is to assume that a broken helmet has prevented some serious injury. Helmets are designed to crush without breaking; EPS absorbs little energy in brittle failure and once it fails no further energy is absorbed. To prevent breakage, the foam in the helmets is reinforced inside with plastic netting to keep the foam together.

Proper fit

It is important that a helmet should fit the cyclist properly – according to research most helmets (well over 90% ^[6]) have been found to be incorrectly fitted. Efficacy of incorrectly fitted helmets is reckoned to be much lower; one estimate states that risk is increased almost twofold^[7].

Most manufacturers provide a range of sizes ranging from children's to adult with additional variations from small to medium to large. The correct size is important. Some adjustment can usually be made using different thickness foam pads. Helmets are held on the head with nylon straps, which must be adjusted to fit the individual. This can be difficult to achieve, depending on the design. Most helmets will have multiple adjustment points on the strap to allow both strap and helmet to be correctly positioned. Additionally, some helmets have adjustable cradles which fit the helmet to the occipital region of the skull. These provide no protection, only fit, so helmets with this type of adjustment are unsuitable for roller skating, stunts, skateboarding and unicycling. For other uses, see Child (disambiguation). ... For the adult insect stage, see Imago. ... For other uses of this word, see nylon (disambiguation). ...

The helmet should sit level on the cyclists head with only a couple of finger-widths between eyebrow and the helmet brim. The strap should sit at the back of the lower jaw, against the throat, and be sufficiently tight that the helmet does not move on the head. It should not be possible to insert more than one finger's thickness between the strap and the throat.

History

"Hairnet" helmet

Prior to the mid-1970s, the dominant form of helmet was the leather "hairnet" style, mainly used by racing cyclists. This offered minimal impact protection and acceptable protection from scrapes and cuts. In countries with long traditions of utility cycling, nearly all cyclists did not and still do not wear helmets. The use of helmet by non-racing cyclists began in the U.S. in the 1970s. After many decades of where cycles were regarded as children's toys, many American adults took up cycling during and after the bike boom of the 1970s. Two of the first modern bicycle helmets were made by MSR, a manufacturer of mountaineering equipment, and Bell Sports, a manufacturer of helmets for auto racing and motorcycles. These helmets were a spinoff from the development of expanded polystyrene (EPS) foam liners for motorcycling and motorsport helmets, and had hard polycarbonate plastic shells. The bicycle helmet arm of Bell was split off in 1991 as Bell Sports, having completely overtaken the motorcycle and motor sports helmet business. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... The 1970s decade refers to the years from 1970 to 1979, also called The Seventies. ... The peloton of the Tour de France Bicycle racing encompasses many forms in which bicycles are used for competition. ... Ugandan bicycle taxi or bodaboda Cargo-bicycle and Trike for rent Bremen. ... The bike boom of the 1970s was a period in which bicycles and cycling became popular among adult Americans, after several decades in which bikes had been relegated to the status of toys. ... MSR WindPro portable stove with heat reflector and wind shield An MSR propane/isobutane fuel canister and portable stove in operaton Mountain Safety Research, or MSR, was founded in 1969 by Larry Penberthy because he was not pleased with the safety and reliability of outdoor eqipment. ... This article does not cite any references or sources. ... Bell Sports Inc. ... Polycarbonates are a particular group of thermoplastic polyesters. ... Year 1991 (MCMXCI) was a common year starting on Tuesday (link will display the 1991 Gregorian calendar). ...

The first commercially successful purpose-designed bicycle helmet was the Bell Biker, a polystyrene-lined hard shell released in 1975. At the time there was no appropriate standard; the only applicable one, from Snell, would be passed only by a light open-face motorcycle helmet. Over time the design was refined and by 1983 Bell were making the V1-Pro, the first polystyrene helmet intended for racing use. In 1984 Bell produced the Li'l Bell Shell, a no-shell children's helmet. These early helmets had little ventilation. Year 1975 (MCMLXXV) was a common year starting on Wednesday (link will display full calendar) of the Gregorian calendar. ... Year 1983 (MCMLXXXIII) was a common year starting on Saturday (link displays the 1983 Gregorian calendar). ... This article is about the year. ...

In 1985 the Snell B85 was introduced, the first widely-adopted standard for bicycle helmets; this has subsequently been refined into B90 and B95 (see Standards below). At this time helmets were almost all either hard shell or no-shell (perhaps with a vacuum-formed plastic cover). Ventilation was still minimal due mainly to technical limitations of the foams and shells in use.

A Giro Atmos helmet, showing seamless in-mould microshell construction.

Around 1990 a new construction technique was invented: in-mould microshell. A very thin shell was incorporated during the moulding process. This rapidly became the dominant technology, allowing for larger vents and more complex shapes than hard shells. Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2272 × 1704 pixel, file size: 622 KB, MIME type: image/jpeg) The side of a Giro Atmos showing in mould construction. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2272 × 1704 pixel, file size: 622 KB, MIME type: image/jpeg) The side of a Giro Atmos showing in mould construction. ... Giro is a U.S. manufacturer of helmets for cycling and snow sports. ... Year 1990 (MCMXC) was a common year starting on Monday (link displays the 1990 Gregorian calendar). ...

Hard shells declined rapidly among the general cyclist population during the 1990s, almost disappearing by the end of the decade, but remain popular with BMX riders as well as inline skaters and skateboarders. A BMX Race. ...

The late 1990s and early 2000s saw advances in retention and fitting systems, replacing the old system of varying thickness pads with cradles which adjust quite precisely to the rider's head. This has also resulted in the back of the head being less covered by the helmet; impacts to this region are rare, but it does make a modern bike helmet much less suitable for activities such as unicycling, skateboarding and inline skating, where falling over backwards is relatively common. Other helmets will be more suitable for these activities. The 2000s are the current decade, spanning from 2000 to 2009. ...

Since more advanced helmets began being used in the Tour de France, Carbon Fiber inserts have started to be used to increase strength and protection of the helmet. The Giro Atmos and the Bell Alchera are among the first to use carbon fiber. The Tour de France is the worlds best-known cycling race, a 22 day long, 20 stage road race that is usually run over a distance of more than 3000km. ... Carbon fiber composite is a strong, light and very expensive material. ... Bell Sports Inc. ...

Helmet regulations in cycling sport

Historically, road cycling regulations set by the sport's ruling body, Union Cycliste Internationale (UCI), did not require helmet use, leaving the matter to individual preferences and local traffic laws. The majority of professional cyclists chose not to wear helmets, citing discomfort and claiming that helmet weight would put them in a disadvantage during uphill sections of the race. Shortcut: WP:-( Vandalism is indisputable bad-faith addition, deletion, or change to content, made in a deliberate attempt to compromise the integrity of the encyclopedia. ... Shortcut: WP:-( Vandalism is indisputable bad-faith addition, deletion, or change to content, made in a deliberate attempt to compromise the integrity of the encyclopedia. ... Entrance of UCI headquarter at Aigle (Switzerland) Union Cycliste Internationale (UCI) is a professional cycling union that oversees cycling events in the international community. ...

The first serious attempt by the UCI to introduce mandatory helmet use in 1991 was met with strong opposition from the riders.^[8] An attempt to enforce the rule at the 1991 Paris-Nice race resulted in riders' strike, forcing the UCI to abandon the idea. Paris-Nice, nicknamed the race to the sun, is an annual professional cycling stage race held annually each March. ...

While voluntary helmet use in professional ranks rose somewhat in the 1990s, the turning point in helmet policy was the March 2003 death of Kazakh Andrei Kivilev. Some officials within UCI had been trying to re-establish a helmet rule, and used this incident to push through the change, initially claiming that it was for insurance reasons although the insurers subsequently denied this. The new rules were introduced on May 5, 2003^[9], with the 2003 Giro d'Italia being the first major race affected. The 2003 rules allowed for discarding the helmets during final climbs of at least 5 kilometres in length;^[10] subsequent revisions made helmet use mandatory at all times. Andrei Kivilev (September 20, 1973_March 12, 2003) was a professional cyclist from Kazakhstan. ... is the 125th day of the year (126th in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... The 86th Giro dItalia was held in 2003 from May 10 to June 1. ...

No studies have been published yet into whether injuries have reduced as a result.

The helmet debate

Are helmets needed?

Ordinary cycling is not demonstrably more dangerous than walking or driving,^[11] yet no country promotes helmets for either of these modes (although there was an experiment in Japan with walking helmets for children, which demonstrated no measurable benefit).^[12] Detailed analysis of hospital admissions data also fails to support the idea that cycling is unusually dangerous: a study in the UK found that the proportion of cyclist injuries which are head injuries is essentially the same as the proportion for pedestrians at 30.0% vs. 30.1%.^[13] Overall, cycling is beneficial to health – the benefits outweigh the risks by up to 20:1.^[14]

Do helmets work?

Evidence for the efficacy of helmets in preventing serious injury is contradictory and inconclusive. The evidence comes from two main types of observational study: case-control studies, and time-trend analyses. Overall, according to CTC, the UK's national cyclists organisation, "the evidence currently available is complex and full of contradictions, providing at least as much support for those who are sceptical as for those who swear by them."^[15] Case-control studies are one type of epidemiological study design. ... CTC, the Cyclists Touring Club, is the United Kingdom and Irelands largest and longest established cycling membership organisation. ...

Case-control studies

Case-control studies compare cyclists who have injured their heads ("cases") and cyclists who have not ("controls"). Case-control studies are one type of epidemiological study design. ...

Known problems with this type of study design include confounding (attributing benefits from unmeasured differences in behaviour to differences in helmet choice), and recall bias (people incorrectly reporting helmet use).^[16] Such studies consistently find that cases of head injury report a lower rate of helmet-wearing than controls who have injured other parts of the body.^[17] This has been taken as strong evidence that cycle helmets are beneficial in a crash. The most widely-quoted case-control study, by Thompson, Rivara, and Thompson, reported an 85% reduction in the risk of head injury by using a helmet. There are many criticisms of this study,^[18] including use of a control group with very different risks. Re-analysis of the Thompson, Rivara and Thompson data, substituting helmet wearing rates from co-author Rivara's contemporaneous street counts^[19], reduces the calculated benefit to below the level of statistical significance.^{[original research?]} In another study, helmet users also seemed to be protected against severe injuries to the lower body. Spaite, Murphy, Criss, Valenzuela and Meislin "conclude that helmet non-use is strongly associated with severe injuries in this study population. This is true even when the patients without major head injuries are analyzed as a group" (page reference needed).^[20] It is possible that at least some of the 'protection' afforded helmet wearers in previous studies may be explained by safer riding habits rather than solely a direct effect of the helmets themselves.^[21] In statistics, a spurious relationship (or, sometimes, spurious correlation) is a mathematical relationship in which two occurrences have no logical connection, yet it may be implied that they do, due to a certain third, unseen factor (referred to as a confounding factor or lurking variable). The spurious relationship gives an... In psychology, recall bias (or reporting bias) is a type of systematic bias which occurs when the way a survey respondent answers a question is affected not just by the correct answer, but also by the respondents memory. ...

Time-trend analyses

Time-trend analyses compare changes in helmet use and injury rates in populations over time, most validly where helmet laws have resulted in large changes in a short time.

Potential weaknesses of this type of study include: simultaneous changes in the road environment (e.g. drink-drive campaigns); inaccuracy of exposure estimates (numbers cycling, distance cycled etc.), changes in the definitions of the data collected, failure to analyse control groups, failure to analyse long-term trends, and the ecological fallacy. Robinson's review of cyclists and control groups in jurisdictions where helmet use increased by 40% or more following compulsion concluded that "enforced helmet laws discourage cycling but produce no obvious response in percentage of head injuries".^[22] Some of the data for this publication is available at [13]. This study has been the subject of vigorous debate.^{[23] [24][25]} Authors do not agree on how studies should be selected for analysis, nor on what summary statistics are most relevant. A more recent review, by Macpherson and Spinks, includes two original papers (neither of which meet the criteria for inclusion in Robinson's review) and concludes that "Bicycle helmet legislation appears to be effective in increasing helmet use and decreasing head injury rates in the populations for which it is implemented. However, there are very few high quality evaluative studies that measure these outcomes, and none that reported data on an possible declines in bicycle use."^[26] The ecological fallacy is a widely recognised error in the interpretation of statistical data, whereby inferences about the nature of individuals are based solely upon aggregate statistics collected for the group to which those individuals belong. ...

There are many other studies. The largest, covering eight million cyclist injuries over 15 years, showed no effect on serious injuries and a small but significant increase in risk of fatality.^[27] Different analyses of the same data can produce different results. For example, Scuffham analysed data on the New Zealand helmet law in 1995 and concluded that, after taking into account long-term trends, the laws had no measurable effect.^[28] His subsequent re-analysis without accounting for the long-term trends showed a small benefit.^[29] Scuffham's later cost-benefit analysis of the New Zealand helmet law showed that the cost of helmets outweighed the savings in injuries, even taking the most optimistic estimate of injuries prevented.^[30]

Positions and arguments

There is contested research, and there are different assessments of what issues are relevant and important. Much of the research is partisan in one way or another. Rodgers re-analysed data which supposedly showed helmets to be effective; he found data errors and methodological weaknesses so serious that in fact the data showed "bicycle-related fatalities are positively and significantly associated with increased helmet use".^[31] One report concluding that helmet use was associated with a 60% reduction in injuries was found to be in error due to a simple statistical error; correcting the error results in a claimed efficacy of 186%; despite this the authors continue to assert that the results stand.^[32] A report commissioned by the UK Government was supportive of cycle helmet promotion^[33] but dismissed much of the contradictory evidence with minimal examination, and the principal authors were associated with a programme of the Child Accident Prevention Trust (CAPT), which is strongly pro-helmet.^[34] Curnow, author of papers on helmets and traumatic brain injury, has also published criticism of pro-helmet research.^[35]

Supporters

Many notable organisations and individuals believe that a helmet can reduce head injuries, and even save a cyclist's life. The World Health Organisation promote the use of helmets as a strategy for preventing head injuries caused by bicycle crashes or falls.^[36] Use of cycling helmets is supported by numerous groups in the United States, including the American Medical Association^[37] and the American National Safety Council.^[38] By 1991, the League of American Wheelmen described bicycle helmets as a "Mom and apple pie" issue in the US.^[39] In 2004 the British Medical Association's Board of Science and Education adopted a position calling on the UK government to introduce cycle helmet legislation, and this was confirmed at the 2005 Annual Representative Meeting following fifteen minutes of debate.^[40][41] The prominent U.S.-based cycling activist John Forester suggests that helmet wearing could save 300 deaths a year in the US, behind Effective Cycling at 500 and ahead of all other interventions, totalling 1,030.^[42] For other meanings of the acronym WHO, see WHO (disambiguation) WHO flag Headquartered in Geneva, Switzerland, the World Health Organization (WHO) is an agency of the United Nations, acting as a coordinating authority on international public health. ... The American Medical Association (AMA) is the largest association of medical doctors in the United States. ... The logo of the association. ... John Forester (born 1929) is a cycling transportation engineer and a noted cycling activist who coined the term Effective Cycling and the vehicular cycling principle: Cyclists fare best when they act and are treated as drivers of vehicles. Forresters outspoken resistance to dedicated bicycle paths ( see Forester Web Site... Effective Cycling is a trademarked cycling educational program designed by John Forester, which was promoted for a number of years by the League of American Wheelmen. ...

Opponents

Amongst those who do not support the arguments in favor of helmet use, or helmet compulsion, are many notable academics, practitioners and cyclists' lobbying groups. Robinson reviewed data from jurisdictions where helmet use increased following legislation, and concluded that helmet use did not demonstrably reduce cyclists' head injuries.^[22] Mayer Hillman, a transport- and road safety-analyst from the UK, does not support the use of helmets, reasoning that they are of very limited value in the event of a collision with a car, that risk compensation negates their protective effect and because he feels their promotion implicitly shifts responsibility of care to the cyclist.^[43][44] He also cautions against placing the recommendations of surgeons above other expert opinion in the debate, comparing it to drawing conclusions on whether it is worthwhile to buy lottery tickets by sampling only a group of prizewinners.^[45] The prominent UK-based cycling activist John Franklin is skeptical of the merits of helmets, regarding proactive measures including bike maintenance and riding skills as being more important.^[46] Cyclists' representative groups complain that focus on helmets diverts attention from other issues which are much more important for improving bicycle safety, such as road danger reduction, training, roadcraft, and bicycle maintenance.^[47][48] Of 28 publicly funded cycle safety interventions listed in a report in 2002, 24 were helmet promotions. For context, one evaluation of the relative merits of different cycle safety interventions estimated that 27% of cyclist casualties could be prevented by various measures, of which just 1% could be achieved through a combination of bicycle engineering and helmet use.^{[citation needed]} Mayer Hillman (born London, 1931) is a Senior Fellow Emeritus since 1992 at the Policy Studies Institute. ...

In 1998 the European Cyclists' Federation adopted a position paper rejecting compulsory helmet laws as being likely to have greater negative rather than positive health effects.^[47] The UK cyclists' club, CTC, believes that the "overall health effects of compulsory helmets are negative."^[49] The UK minister of transport knew of no evidence to support the claim that helmets saved lives. ^[50] The British National Children's Bureau has said "The 2004 BMA statement announcing its decision to support compulsory cycle helmets shows how the uncritical use of accident statistics can lead to poor conclusions."^[51] The same report estimated that, at most, universal helmet use would save the lives of three children aged 0 to 15 each year. That figure "assumes universal and correct use of helmets, it assumes that risk compensation does not occur and it assumes that no children die as a result of strangulation or other injuries caused by helmet use. These assumptions are most unlikely to be correct in the real world." CTC, the Cyclists Touring Club, is the United Kingdom and Irelands largest and longest established cycling membership organisation. ... The National Childrens Bureau is a childrens charity based in Islington, London. ...

Influencing helmet use

There is a long-running argument over the use, promotion, and compulsion of cycle helmets. Helmet use has increased significantly in many, but not most, jurisdictions since the 1980s, primarily because of helmet promotion and compulsion laws. Most heated controversy surrounds laws making helmet use compulsory.

Promotion

Significant helmet promotion preceded epidemiological studies evaluating the effectiveness of bicycle helmets in bicycle crashes.^[52][53]

Dismissing concerns in 1996 that helmets should be shown to actually reduce injury rates, two pro-helmet doctors asked "How robust must the evidence be when the benefits of wearing helmets are so patently obvious? What is the downside to wearing a helmet, other than the mussing of Minerva's hair?".^[54] One of these, himself a cyclist, started his "career of advocacy" in 1972 and is now editor of an academic journal on injury prevention.^[55] In this position he has found "tiresome" academic argument that helmet wearing is useless.^{[56][57][58][59]}

Rivara was already engaged in surveying and lobbying for helmet use before the influential Thompson, Rivara and Thompson case-control study was commenced in 1989,^[19] while the report by Thompson, Rivara and Thompson for the Cochrane review has been criticised for being dominated by their own work.^{[citation needed]} The Cochrane Collaboration developed in response to Archie Cochranes call for systematic, up-to-date reviews (currently known as systematic reviews) of all relevant randomized clinical trials of health care. ...

Promotion of helmets raises further issues. Helmet promoters routinely make claims which manufacturers cannot, due to restrictions on advertising claims.^{[original research?]} Promotion campaigns are often supported and/or funded by manufacturers.^{[citation needed]} Bell, one major helmet manufacturer, supports both helmet promotion and, through its Legislative Assistance Programme, laws.^{[citation needed]}

From the point of view of cycling activists, the major problem with helmet promotion is that in order to present the idea of a "problem" to match the solution they present, promoters tend to overstate the dangers of cycling.^{[original research?]} Cycling is no more dangerous than being a pedestrian.^[60]

Legislation

The following countries have mandatory helmet laws, in at least one jurisdiction, for either minors only, or for all riders: Australia, Canada, Finland, Iceland, Israel,^[61] Sweden, USA, and New Zealand. In the U.S. 37 states have mandatory helmet laws.^[62] Although the link is not causal, it is observed that the countries with the best cycle safety records (Denmark and the Netherlands) have among the lowest levels of helmet use.^[63] Their bicycle safety record is generally attributed to public awareness and understanding of cyclists, safety in numbers, education, and to some extent separation from motor traffic.^{[citation needed]} Safety in numbers is the theory that by being part of a large group, an individual member is proportionally less likely to be the victim of a mishap, accident, or other bad event. ... This article needs additional references or sources for verification. ...

A study of cycling in major streets of Boston, Paris and Amsterdam illustrates the variation in cycling culture: Boston had far higher rates of helmet-wearing (32% of cyclists, versus 2.4% in Paris and 0.1% in Amsterdam), Amsterdam had a far higher numbers of cyclists (242 passing bicycles per hour, versus 74 in Paris and 55 in Boston).^[64] Received opinion in some English-speaking countries is that bicycle helmets are useful and that every cyclist should wear one; helmets had become a ‘ “Mom and apple pie” issue’ in the United States by 1991 according to the League of American Bicyclists.^[65] Cycle helmet wearing rates in the Netherlands and Denmark are very low.^[44] The UK's CTC say that cycling in the Netherlands and Denmark is perceived as a "normal" activity requiring no special clothing or equipment.^[66] The Dutch Institute for Road Safety Research (SWOV) advocates helmet use and helmet laws to further improve cycling safety.^[67]

Side-effects of helmet use

Concerns have been raised that mandatory bicycle helmet laws lead to a reduction in the number of cyclists, and increased helmet use may lead to increased risk taking.

Less bicycle use

When mandatory bicycle helmet laws were enacted in Australia, slightly more than one third of bare-headed cyclists ceased to ride their bicycles frequently.^[68] The reduction in the number of cyclists is likely to harm the health of the population more than any possible protection from injury.^[69] The long term health benefits of bicycle use are manifold and extensively documented, and so any reduction in bicycling will likely have a negative impact on the overall health of a population.^[70] It has been suggested that a fall in the number of bicyclists in the 1990s may reflect an increase in in-line skating or other recreational activities,^[24] or the evidence that helmet promotion deters cycling has been simply denied.^[26]

Several mechanisms by which cycle helmet promotion or compulsion may deter cycling have been suggested. Helmets and their promotion may reinforce the misconception that bicycling is more dangerous than traveling by passenger car.^[71] Referring to the use of "human skull" images in a campaign,^[72] the CTC suggests that "this macabre imagery, with its associations of hospitals and death, is likely to reduce cycle use, thereby undermining efforts to realise the health and other benefits of increased cycling".^[73] Cycle helmets cost money and may make cycling less convenient; they are bulky and often cannot be stored securely with bikes. They are incompatible with some hairstyles, forcing bicycle users to recreate their hairstyle after each journey. Finally, bicycle "crash-helmets" have been seen as ridiculous. For example, in the 2006 film The Benchwarmers, the character Clark — played by Jon Heder — sports a bicycle crash helmet as an accessory prop to highlight his lack of social skills and physical coordination. A bicycle rack is a device to which a bicycle can be securely attached to prevent theft. ... Street haircut in Harbin, China For humans, haircut, hairstyle, or hairdo normally describe cutting or styling head hair. ... This article does not cite any references or sources. ... Jonathan Michael Heder (born October 16, 1977[1]) is an American actor and filmmaker. ...

More danger for other cyclists

A reduction in cycling may lead to an increased risk for the cyclists remaining on the road, due to a "safety in numbers" effect.^[74] According to one source, the probability of an individual cyclist being struck by a motorist declines with the 0.6 power of the number of cyclists on the road.^[11] This means that if the number of cyclists on the road doubles, then the average individual cyclist can ride for an additional 50% of the time without increasing his probability of being struck. It is thought that the increased frequency of motorist-cyclist interaction creates more aware motorists. Safety in numbers is the theory that by being part of a large group, an individual member is proportionally less likely to be the victim of a mishap, accident, or other bad event. ...

Increased cyclist risk

Association with increased risk has been reported.^[75][27][20] Although the head injury rate in the US rose by 40% as helmet use rose from 18% to 50%, this does not necessarily mean that helmets themselves increase risk. In fact, a range of theories exist which may explain the correlation between helmet use and accidents. Lets talk about risk control strategies, anyone with more information and willing to share, please do so. ...

Under the risk compensation theory, helmeted cyclists may be expected to ride less carefully; this is supported by evidence for other road safety interventions such as seat belts and anti-lock braking systems.^[76][77] Risk compensation by children in relation to safety equipment has been demonstrated.^[78] In ethology, risk compensation is an effect whereby individual animals may tend to adjust their behaviour in response to perceived changes in risk. ... This article does not cite its references or sources. ... An anti-lock braking system (ABS) (translated from German, Antiblockiersystem) is a system on motor vehicles which prevents the wheels from locking while braking. ...

Recent evidence from England found that vehicles passed helmeted cyclists with measurably less clearance (8.5 cm) than that given to unhelmeted cyclists (out of an average total passing distance of 1.2 to 1.3 metres), indicating risk compensation by motorists.^[79]

Poor fitting is usual and has been estimated to double the risk of injury ^[80][81]

Recent research on traumatic brain injury adds further confusion, suggesting that the major causes of permanent intellectual disablement and death may well be torsional forces leading to diffuse axonal injury (DAI), a form of injury which helmets cannot mitigate and may make worse.^[82] Helmets may increase the torsional forces by increasing the distance from the extremities of the helmet to the centre of the spine, compared to the distance without a helmet. Traumatic brain injury (TBI), traumatic injuries to the brain, also called intracranial injury, or simply head injury, occurs when a sudden trauma causes brain damage. ... This article or section does not adequately cite its references or sources. ... Torque applied via an adjustable end wrench Relationship between force, torque, and momentum vectors in a rotating system In physics, torque (or often called a moment) can informally be thought of as rotational force or angular force which causes a change in rotational motion. ... Diffuse axonal injury (DAI) is one of the most common and devastating types of brain injury (Iwata , 2004), occurring in almost half of all cases of severe head trauma (Park and Hyun, 2004). ... Torque applied via an adjustable end wrench Relationship between force, torque, and momentum vectors in a rotating system In physics, torque (or often called a moment) can informally be thought of as rotational force or angular force which causes a change in rotational motion. ...

See also

• Car headband
• Motorcycle helmet

The Car headband is a protective headband concept for car occupants being investigated by the Centre for Automotive Safety Research(CASR), University of Adelaide, Australia. ... // A motorcycle helmet is a type of protective headgear used by motorcycle riders. ...

References

Case studies

• Thompson, R., Rivara, F. and Thompson, D. (1989), A Case-Control Study of the Effectiveness of Bicycle Safety Helmets, New England Journal of Medicine, 25 May, 320:21, 1361–67 Abstract — (The most widely cited pro-helmet study.)
• Scuffham Trends in cycle injury in New Zealand under voluntary helmet use, Langley. Accident Analysis and Prevention, Vol 29:1, 1997 — (Showed no benefit from large-scale increases in helmet use.)

The New England Journal of Medicine (New Engl J Med or NEJM) is a peer-reviewed medical journal published by the Massachusetts Medical Society. ... is the 145th day of the year (146th in leap years) in the Gregorian calendar. ...

Risk

• John Adams, 1995, Risk, Routledge, ISBN 1-85728-068-7 — (Authoritative reference on risk compensation theory.)

Compulsion Laws

• BikeBiz (industry journal), "Helmet battle flares up in BMJ", March 24, 2006
• BikeBiz (industry journal), "Let's fight for our rights to the road, argues CTC", Feb 27th 2006
• D Hendrie, M Legge, D Rosman, C Kirov, "An economic evaluation of the mandatory bicycle helmet legislation in Western Australia", Road Accident Prevention Research Unit, Department of Public Health, The University of Western Australia.
• Merton, R.K., "The Unanticipated Consequences of Purposive Social Action", American Sociological Review, Vol.1, No.6, (December 1936), pp.894–904. (see Unintended consequence)
• Scuffham, Alsop, Cryer, Langley, "Head Injuries to Cyclists and the New Zealand Cycle Helmet Law", Accident Analysis and Prevention, 2000, 32: 565–573
• Vulcan, A.P., Cameron, M.H. & Heiman, L., "Evaluation of mandatory bicycle helmet use in Victoria, Australia", 36th Annual Conference Proceedings, Association for the Advancement of Automotive Medicine, Oct 5–7, 1992.
• Vulcan, A.P., Cameron, M.H. & Watson, W.L., "Mandatory Bicycle Helmet Use: Experience in Victoria, Australia", World Journal of Surgery, Vol.16, No.3, (May/June 1992), pp.389–397.

is the 83rd day of the year (84th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... This article or section does not cite any references or sources. ...

Notes

CTC may stand for: Calcutta Tramways Company California Commission on Teacher Credentialing Canada Tibet Committee Canadian Tire Corporation Canadian Tourism Commission Capital Terminus Collective Carbon tetrachloride Celebrate the Century, a postage stamp series published by the United States Postal Service Central Texas College Central de Trabajadores de Cuba, Workers Central... The Department of Health headquarters in Whitehall The Department of Health is a department of the United Kingdom government. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 237th day of the year (238th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 240th day of the year (241st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 84th day of the year (85th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 242nd day of the year (243rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 237th day of the year (238th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 237th day of the year (238th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 249th day of the year (250th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 181st day of the year (182nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 236th day of the year (237th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 236th day of the year (237th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 236th day of the year (237th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 243rd day of the year (244th in leap years) in the Gregorian calendar. ... Year 1995 (MCMXCV) was a common year starting on Sunday (link will display full 1995 Gregorian calendar). ... is the 48th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 208th day of the year (209th in leap years) in the Gregorian calendar. ... Year 1996 (MCMXCVI) was a leap year starting on Monday (link will display full 1996 Gregorian calendar). ... is the 138th day of the year (139th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 236th day of the year (237th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 236th day of the year (237th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 236th day of the year (237th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 236th day of the year (237th in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Pediatrics is an official peer-reviewed journal of the American Academy of Pediatrics. ... is the 214th day of the year (215th in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ...

External links

Wikimedia Commons has media related to:

Bicycle helmets

• A synopsis of selected research papers and medical articles - from RoSPA
• Bicycle Helmet Research Foundation
• Chris Gillham, Mandatory bicycle helmet law in Western Australia
• John Franklin, Cycle helmet resources
• Ontario Coalition for Better Cycling, "Helmet FAQ"
• Randy Swart, "Bicycle Helmet Safety Institute"
• Snell Memorial Foundation, "Active list of certified helmets"
• U.S. Consumer Product Safety Commission, "CPSC publication announcing new US helmet standard"
• Review of a new folding crash helmet for bicycle riders