More strong performers in new batch of bike helmet ratings
December 18, 2018
The Virginia Tech Helmet Lab has released ratings for 20 additional bicycle helmets, supplementing the initial set of 30 ratings published earlier this year.
The ratings give each helmet a score between one and five stars that reflects its ability to reduce the risk of head injuries. Six helmet models in the new batch earned all five stars, and nine models earned four stars.
The Bontrager Ballista MIPS, which scored highest in the first set of ratings, held onto its spot at the top of the pack.
“There’s a huge array of choices in the bike-helmet market; our goal with the ratings is to give cyclists an evidence-based way to make informed decisions about how to reduce their risk of head injury,” said Steve Rowson, an associate professor of biomedical engineering and mechanics in the College of Engineering and the helmet lab’s director. “We targeted some of the most popular models in our first set of ratings, and now we’re expanding outward so that we can reach as many consumers as possible.”
Cycling is associated with a higher number of sports-related head injuries than any other activity, primarily because it’s so popular: More than a third of Americans rode a bike in the past year.
Those cyclists have hundreds of helmets to choose from, and they’re all required to meet a safety standard set by the Consumer Product Safety Commission. But all a helmet has to do is perform well enough to pass an impact test calibrated for exceptionally severe injuries, like skull fractures, so there’s no way for consumers to tell the difference between a helmet that skated by and one that passed with flying colors.
Or there wasn’t, until the lab released the first set of bike helmet ratings over this past summer, the culmination of two years of research and testing in collaboration with the Insurance Institute for Highway Safety. The five-star scale clarifies the relative differences between helmets, allowing consumers to see which ones protect heads better than others.
The Virginia Tech Helmet Lab has been rating protective headgear since 2011. They started with football helmets, then expanded to hockey, soccer, and now cycling (and more sports are in the works). Intended to infuse some science into the sometimes arbitrary process of helmet selection, the ratings have also helped guide manufacturers in the design of safer equipment.
As with every sport in their portfolio, the team developed the bike helmet ratings by studying the circumstances of real-world impacts, then meticulously recreating them in the lab with a custom-built impact rig.
In the setup they designed for bike-helmet testing, a dummy headform snugly fitted with a helmet plummets down a drop tower onto an anvil. The anvil is tilted, because most crashes occur at an oblique angle, and covered with sandpaper to mimic the friction between a helmet and the road.
At the moment of impact, sensors embedded in the headform measure its linear acceleration and rotational velocity, two parameters associated with head injury risk. The process is repeated at six different impact locations and two impact speeds for each helmet model. The researchers then combine the data to calculate how much the helmet mitigates the force of an impact and translate that into a score of one, two, three, four, or five stars.
The lab is continuing to test more helmet models and update the ratings as new data is available. The Insurance Institute for Highway Safety funded the project and contributed to the research.