The Complicated Story Behind Bike Helmet Safety

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Why ensuring bike helmet safety is trickier than you might think—and what one lab is doing about it.

It’s obvious why we wear helmets while riding a bicycle. Research shows that cycling is responsible for more head injuries than any other sport or recreational activity. So even though we don’t intend to crash on our bike when we start pedaling, a helmet is an assurance that if we do crash, a layer of hard EPS foam will take the brunt of the impact. 

Yet, no helmet is as fool-proof as consumers may think. 

“Here’s the bottom line: Every single bike crash is different,” said René Costales, REI’s senior category merchandising manager for bike and snow accessories. “We don’t know exactly how to perfectly test for the safety of a helmet in all scenarios. That’s the inconvenient truth about bike helmets.”

Even as helmets incorporate new technologies like MIPS or Wavecel to offer more protection against concussions, federal testing standards are lagging and outdated. Most helmet manufacturers conduct their own internal testing, but the results of the test can be skewed by the method or context, and this leaves consumers in a bind. How much can we trust a company’s claim about their helmet? 

The Helmet Lab at Virginia Tech offers independent, third-party testing on football, hockey and bike helmets, among other sports such as soccer or baseball. By testing bike helmets for their ability to protect against brain injury, they complement the federal standard test. 

In total, the lab has tested and rated 69 bike helmets. The top 20 are all made with either MIPS or Wavecel, which speaks to the effectiveness of these technologies at reducing some of the rotational forces. Megan Bland, a research assistant at the Helmet Lab, thinks these new technologies are very promising in terms of offering protection against head injuries, especially compared to a basic foam helmet without a rotational component. But she stopped just shy of saying one was better than the other.  

“I think manufacturers are doing a great job of pushing the boundaries,” said Bland. “At the end of the day, everyone is showing that they’re better than nothing.”

Why cycling causes so many head injuries, and why it’s so hard to study them

According to data collected by the United States Consumer Product Safety Commission (CPSC), of the 446,788 sports-related head injuries treated at U.S. hospital emergency rooms in 2009, cycling was responsible for 85,389 of them. Football was second, with 46,948 head injuries. Experts in helmet testing presume that more people ride bicycles than play football. According to the Centers for Disease Control and Prevention, bike accidents cause 26,000 traumatic brain injuries to children and adolescents, annually.

At the Helmet Lab at Virginia Tech, researchers evaluate how athletes experience head injuries and how helmets work to prevent them. Even with such straightforward objectives, bicycling can be a confounding area of study because it’s difficult to collect data that informs exactly how people fall off their bikes.   

“We’ve tried to do our best to replicate real-world scenarios, but cycling is the most challenging,” said Barry Miller, director of outreach for the Helmet Lab.

The biggest reason why it’s so hard to collect data is largely because cyclists don’t expect to crash, and when they do, the circumstances of their crash are unique and varied. “Usually these impacts are accidental, or they’re not intentional,” said Bland. “So we can’t put thousands of dollars worth of instrumentation on someone and ask them to crash, and we don’t have good quality video to figure out what typical cyclist head-impact conditions are.”

How researchers test bike helmets

The Consumer Product Safety Commission (CPSC) conducts standardized testing and certifies all bike helmets sold in the United States. By measuring linear forces—dropping a helmet vertically onto a perpendicular test surface—the CPSC test reveals how effective a helmet is at protecting against severe injuries, like skull fractures. Experts like Bland say the test is important to prevent catastrophic injury, but it is ineffective in testing new technologies like MIPS and Wavecel that work against rotational forces. 

“While the standards [testing] may be a low bar of sorts, they have a really important function, in my opinion,” said Bland. “They evaluate a severe-impact scenario.”

Meanwhile, companies are conducting their own internal testing, and often the context or method of the test plays a big role in steering the outcome, said Bland. Wavecel, for example, used a “neck” in their test, while other tests don’t.

Without a standard to test the rotational element of a helmet, researchers at Virginia Tech’s Helmet Lab looked to the research to come up with their own methodology for testing bike helmets. Bland relied on peer-reviewed, scientific literature that computes the mathematical parameters of a bike accident. She also recently took helmets that had been worn in a real-world bicycle crash and, based on the indentation in the helmet, reverse-engineered the accident to understand the impact conditions.

“If you or I were falling from a bike, we’d have a horizontal velocity. We’d be moving in multiple directions,” said Bland. “We’d be coming down to the ground from the vertical, and we’d have some horizontal speed. So we’d actually hit the ground at an angle.” 

Virginia Tech tests helmets with an anvil set at a 45-degree angle and a piece of sandpaper on its surface to simulate road grit. They test each bike helmet model in six different locations, at high and low energies that mimic the speed the force at which a rider falls. The higher energy point represents the worst 10 percent of impacts, said Miller. The lower energy point represents about 50 percent of falls. 

What bike helmets actually do to protect us from head injuries

While hard foam offers protection against a linear drop, it doesn’t do much to lessen the rotational forces of a fall from causing a head injury, said Bland. Even the CPSC says that no helmet has been proven to protect against concussions; rather, the materials are designed to absorb the forces of energy that occur in a fall and cause skull fractures or concussions. 

But several new technologies have recently arrived on the market with the aim to prevent concussions, which are a result of linear or rotational—or a combination—forces of energy on your head.  

MIPS, or Multi-Directional Impact Protection System, is the most pervasive of these technologies. Developed by scientific and medical researchers in Sweden in the late 1990s, the MIPS system is designed to be incorporated in almost any helmet on the market. It can now be found in helmets made by virtually all the big manufacturers in cycling, snow and other sports.

MIPS may be the most widely available, but it’s not the only one. The market is full of bike helmets made with different rotational technologies that all claim to achieve the same goal. Most recently, in March, Bontrager unveiled Wavecel, a honeycomb-esque layer of plastic in the helmet that, as the company describes, “flexes, crumples and glides” to absorb lateral and rotational energy forces upon impact. According to Bontrager and their development partners’ internal testing, Wavecel is 48 times more effective at protecting your head from injuries than a basic EPS foam helmet. 

“The best thing that I can say, is that we have seen promise that almost every helmet with some sort of rotational technology, whether that’s MIPS or Wavecel or a bunch of other ones, have shown promise in reducing overall concussion likelihood compared to your standard foam helmet,” said Bland. “I think manufacturers are doing a great job of pushing the boundaries. And while it seems ... like it’s almost a battle, saying ‘This is the best kind of technology,’ I think at the end of the day, everyone is showing that they’re better than nothing. So it really is a positive result overall. It’s just easy to get caught up in the marketing a little bit.”


Editor's noteEvery helmet sold by REI meets all regulatory requirements; even the most inexpensive, basic helmet will help to keep you safer when you ride (or ski). Third-party testing is one of a variety of factors the co-op takes into consideration when thinking through our helmet assortment, including safety rating, fit, function, accessibility and price.

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