Protection levels of different bicycle helmets revealed by new reviews

Cyclists choosing a new helmet can see how much protection different helmets offer, thanks to new safety tests and ratings from Imperial College London.

Researchers from Imperial College London have developed a simple new safety rating system for bicycle helmets, with easy-to-understand 0-5 scores, designed to help buyers select the right helmet and help manufacturers design future helmets. The system is based on extensive new safety testing experiments on medium-sized helmets at Imperial.

Tests on the 30 most popular helmets in the UK showed significant differences in performance, with no correlation between the price of a helmet and the level of safety it offers the wearer. For example, a £130 helmet performed no better in tests than a £40 helmet.

People can check the rating of the adult bicycle helmets tested so far for the helmet’s impact protection effectiveness rating (Hiper) websiteand the team plans to add classifications for children’s helmets after further research.

Lead author Dr Claire Baker, from Imperial’s Dyson School of Design Engineering, said: “Until now, there has been limited information on how well cyclists can expect their helmet to protect them in the event of an impact to the head. This is because current safety standards are simply pass/fail and only test for direct impacts involving direct impacts to the head. However, evidence from previous studies shows that permanent brain damage occurs in more severe impacts or when the head undergoes rapid rotations during an impact.”

The results are published today in Annals of biomedical engineering.

No correlation between price and protection

Cycling is a cost-effective and environmentally friendly way to get to work. It also improves cardiovascular health, muscle strength and joint mobility with a low impact on health. It can also improve mental health.

Cycling-related injuries and deaths have declined in recent years. However, cyclists remain vulnerable road users and cycling accidents can be serious, with head injuries being one of the leading causes of death and life-changing injuries for cyclists involved in collisions. However, helmet costs and designs vary widely and, until now, there has been no objective assessment information on which helmets available to buy in the UK offer cyclists the best protection.

To compile the rankings, Imperial’s team tested 30 of the most popular adult helmets on the market, all in size medium. The rankings were based on a combination of lab testing, data from major retailers, and a survey of more than a thousand cyclists.

All bicycle helmets sold, including all helmets tested in this study, must meet legal standards to ensure they provide protection.

Dr Baker said: “All helmets sold in Europe must meet the minimum safety standard EN1078, but we wanted to determine whether some helmets offered better protection than others in real-world crash tests. We developed a simple scoring system to rate helmets based on the risk of head injury during a crash. The risk of injury took into account the likelihood of deep brain injury from head rotation, as well as more surface-level injuries and possible skull fractures from direct impact. Our scores range from zero for less protection to five for the best on the market.

“Interestingly, we found no correlation between price and protection, with the best performing helmet being one of the cheaper ones, retailing at around £50. Our new ratings give consumers objective, evidence-based data to support their purchasing decisions.”

Previous studies have shown that head rotation is often associated with loss of consciousness and injuries deep in the brain that can be life-changing, such as causing dementia.

The overall risk was calculated as an average of the linear and rotational risks, assuming they are equally important and present in real victims. However, the researchers say that the weighting of these risks will need to be adjusted in the future as more data becomes available on the distribution of these injuries and their consequences.

The study found that a large proportion of the adult population of all genders wear medium-sized helmets. The use of only medium-sized helmets in this study, which fit the 57 cm circumference test headform, means that future work will test a wider range of helmet sizes to ensure fairness.

Lead author Dr Mazdak Ghajari, also from the Dyson School of Design Engineering at Imperial, supervised the research and is also a member of the working group responsible for one of the European standards on helmet safety (CEN/TC158/WG11).

He said: “The science of brain biomechanics has advanced enormously and we now know much more about how best to protect the human head from serious and long-term injuries in a crash. We are sharing our findings with helmet manufacturers and those responsible for setting testing standards so that the industry can keep pace and develop products that offer the best possible protection… our research can now help consumers make an informed choice when buying a helmet. We believe these assessments will lead to further improvements in helmet design, ensuring they offer better protection against a range of head and brain injuries if a cyclist is involved in a fall or crash.”

Dr. Ghajari and his team plan to apply their testing and evaluation techniques to children’s helmets, as well as continue testing the wide range of adult helmets available.

Ruth Purdie OBE, Chief Executive of The Road Safety Trust, said: “In the event of a collision, cycle helmets can play a vital role in preventing and reducing the severity of head injuries, which is why this new rating system is incredibly important. It will show cyclists which helmets offer the best protection, allowing them to make more informed choices.”