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Posts Tagged ‘helmets’

France has taken a u-turn in its efforts to promote safe and convenient cycling. Thanks to a new law, kids aged 12 and under will be required to wear bike helmet. Failure to do so risks a whopping 135 euro fine. The rule applies even to kids riding in a bike trailer.

The new law was announced at the end of 2016 and is part of a raft of measures contained in a report published last October by a government committee for road safety, following a recent rise in road fatalities. The other measures include fines for drivers caught using their mobile phones while driving and stiffer penalties for speeding.

Youth helmet bills are largely based off a law passed by California back in 1994. The California law has been quite ineffective, and yet it is still being used as a model.

baby2

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You see these stories in the news all the time. A bicyclist gets hit by a car and suffers a major head injury. It could have been much worse, we are told, but thankfully he was wearing a helmet. A shattered bike helmet is shown, with the implication that this could have happened to his skull:

helmet

While pictures like this are scary and dramatic, they are actually further evidence that bike helmets are ineffective. This helmet did not function in the way it was intended. In fact, it failed spectacularly.

Let’s review the physics of a bike helmet. They are constructed out of polystyrene foam (styrofoam) which is supposed to compress in a collision. This compression spreads the force out and reduces the acceleration of the brain as it smashes into the inside of the skull. At least that is how it is supposed to work — under ideal laboratory conditions where the impact force is perpendicular to the helmet. Actual collisions are chaotic events involving complex interactions. When subject to an oblique impact, the styrofoam will typically crack and break off without compressing. This is what appears to have occurred in the helmet shown above. If there is no compression, then it is unlikely the helmet absorbed the impact.

What is unfortunate about these kinds of news stories is that they give false hope about the effectiveness of bike helmets. And rarely do these stories ever mention the dangerous road infrastructure that caused the crash to happen in the first place.

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We all know that mandatory helmet laws discourage cycling. But even after such laws are repealed, the effects can linger:

The city of Dallas has decided that Edward Adkins doesn’t need a bicycle helmet or a bogus fine and arrest warrant hanging over his head.

Adkins received a $10 ticket for failing to wear a bicycle helmet in September 2014, even though the Dallas City Council had changed the city’s safety ordinance months earlier to only apply to minors. Adkins said he couldn’t afford the ticket, which caused the fine to balloon to $259 and turn into a warrant for his arrest.

Adkins said he didn’t show up to court because he didn’t have the money to pay and thought he was guilty. He didn’t know the law didn’t require him to wear a helmet until a reporter told him.

He ended up giving away his bicycle because he didn’t want to pay for a helmet.

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Australia’s mandatory helmet law provided the ideal experiment for testing the effectiveness of bike helmets. The result of that experiment was that helmet laws were completely ineffective.

That negative result should have led to the law being rescinded, but instead they are going full-retard on helmet laws:

Australia’s newest piece of criminal legislation is among the toughest in the world. The target: cyclists.

In a week, riders in Sydney and the rest of New South Wales state will be subject to a package of new laws aimed at cutting deaths and the more than 1,000 serious injuries a year among cyclists. The penalty for cycling without a helmet more than quadruples to A$319 ($229), stiffer than many speeding fines for drivers, and riders jumping a red light will get a A$425 fine. Adult riders will have to carry identification, or face a A$106 penalty from March 2017.

“This legislation is reaching new lows,” said Chris Rissel, a professor at the University of Sydney’s school of public health who has researched the benefits of cycling for 15 years. “There are many things that could be done to make cycling safer and to encourage more people to ride. These things are not it.”

Tougher rules, which come into force March 1, are needed because on average 11 cyclists die and 1,500 are seriously injured each year in New South Wales, said Bernard Carlon, executive director of the government’s Centre for Road Safety.

“If one cyclist chooses to now wear a helmet because of the new penalties, we consider that a win for cyclist safety,” Carlon said in an e-mail.

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There are two popular ways for measuring the safety benefit of bicycle helmets. One method is to look at hospital admission records, comparing the relative number of helmeted and non-helmeted patients. The use of hospital records is an indirect measure, because researchers don’t have reliable data on the number of helmeted cyclists in the general population. Due to this limitation, researchers guesstimate risk exposure rates, which is difficult.

The other method is to study the effect of mandatory helmet laws. A time-series analysis of crash-data before and after implementation of a helmet law provides a direct measure of helmet effectiveness. This is the preferred method because it covers a much larger population in real-world conditions (without having to infer risk exposure rates). Time-series studies of helmet laws in Australia, Canada, and Spain have found no discernible impact on bicycle safety.

When direct measurements of helmet laws failed to find any safety benefit, that should have ended helmet debates. But like any zombie idea, the helmet issue shambles along. Why is that? Perhaps one reason is the hospital case-control studies that promised huge safety benefit from helmets (as high as 85%). But what is the reason for the huge discrepancy between direct and indirect measurements?

One reason for the discrepancy may be due to a methodological error in the hospital case-control studies. That is according to a new paper, Overestimation of the effectiveness of the bicycle helmet by the use of odds ratiosby Th. Zeegers. It was presented at the 2015 International Cycling Conference held last month in Hanover, Germany.

Zeegers argues that case-control studies overestimate the risk of cycling for the control (i.e. non-helmeted cyclists) thereby exaggerating the benefit of helmets. He then re-analyzed data from three popular helmet studies. After correcting for the error, he found that the supposed benefit of bike helmets completely vanished:

Due to lack of data on exposure rates, odds ratios of helmeted versus unhelmeted cyclists for head injury and other injuries on hospitalized victims are broadly used in case-control studies. A general necessary and sufficient condition can be formulated rigorously, for which odds ratios indeed equal risk ratios. However, this condition is not met in case-control studies on bicycle helmets. As a consequence, the real risk of cycling with a helmet can be underestimated by these studies and therefore the effectiveness of the bicycle helmet can be overestimated. The central point is that a wrong estimate of the risk for non-head injuries (the controls) paradoxically can lead to an overestimation of the usefulness of the helmet in protecting against head injuries.

Three cases could be found in the literature with sufficient data to assess both risk ratios and odds ratios: the Netherlands, Victoria (Australia) and Seattle (U.S.A). In all three cases, the problem of overestimation of the effectiveness of the helmet by using odds ratios did occur. The effect ranges from small (+ 8 % ) to extremely large ( > + 400 %). Contrary to the original claim of these studies, in two out of three cases the risk of getting a head injury proved not to be lower for helmeted cyclists. Moreover, in all three cases the risk of getting a non-head injury proved to be higher for cyclists with a helmet.

It must be concluded that any case-control study in which the control is formed by hospitalized bicyclists is unreliable and likely to overestimate the effectiveness of the bicycle helmet. As a direct consequence, also meta-analyses based on these case-control studies overestimate the effectiveness of the bicycle helmet. Claims on the effectiveness of the bicycle helmet can no longer be supported by these kind of studies. This might explain the discrepancy between case-control studies and other studies, such as time-analysis. It is recommended to use other methods to estimate the risk ratio for the bicycle helmet, along the lines described in this article.

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Tricycles: threat or menace?

The helmet fear-mongers go full-retard:

For the past decade, we’ve drilled into children that when they ride a bike, they need to wear a helmet. Now scientists say it may be too late: Tricycle riders should be wearing them, too.

Using data collected from 100 emergency rooms for the National Electronic Injury Surveillance System, researchers found that boys are more likely than girls to turn up in the emergency room. Two-year-olds seem to have the most accidents, although there were tricycle injuries for children up to age 7. The most common broken bone was the elbow and the most common injury overall was a cut to the face.

In addition to helmets, the authors suggest kids wear elbow pads, and that parents supervise their children while they ride.

Even better, just make them wear bubble-wrap.

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Helmet hysteria strikes again. This time, female lacrosse players in Florida are the victims:

Boys’ lacrosse teams nationwide have worn hard-shell helmets for many years. Girls, who play by vastly different rules that generally forbid contact, have historically spurned most protective gear. In Florida, where lacrosse is a new sport, state officials instead reasoned that all lacrosse players are at risk for head trauma and defied the sport’s traditionalists by mandating a soft form of headgear for everyone in a girls’ lacrosse game or practice.

Ann Carpenetti, vice president of lacrosse operations at US Lacrosse, the sport’s national governing body, called Florida’s decision “irresponsible” and said the headgear decision could make the game more hazardous because it might embolden players to be more aggressive.

Coaches across the state have panned the new rule. “It serves no purpose, other than being a costly distraction to parents and the players,” said Nikki Krakower, the coach of the girls’ team at Gainesville High School. “It’s ridiculous.”

Opponents of the mandate said the new rule was especially flawed because the Florida-approved headgear — the type used most commonly is a 10-millimeter-thick headband — is flimsy. “A headband is only going to prevent minor contusions and abrasions if they happen in the two inches the headband covers,” said Lynn Millinoff, the coach of the girls’ team at Buchholz High School in Gainesville. “But Florida officials seem to think they’re smarter than the entire rest of the lacrosse-playing world.”

As you can see from the picture, the thing isn’t even a helmet. Other than perhaps serving as a hair band, it doesn’t serve any purpose.

lacrosse

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