Cycle helmet safety ranked by new Imperial research

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

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

Until now, there has been limited information about how well cyclists can expect their helmet to protect them during head impact. Dr Claire Baker Dyson School of Design Engineering

Testing on the UK’s 30 most popular helmets, funded by The Road Safety Trust, revealed significant differences in performance with no link between the price of a helmet and the level of safety it provides the wearer. So, for example a helmet costing £130 did not perform better in tests than one costing £40.  

People can check the rating of the adult cycle helmets tested to date on the helmet impact protection effectiveness rating (Hiper) website, and the team plan to add ratings for children’s helmets following further research.  

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

The results are published in Annals of Biomedical Engineering. 

No correlation between price and protection 

We found no correlation between price and protection, with the highest-performing helmet being one of the less expensive, retailing at around £50. Dr Claire Baker Dyson School of Design Engineering

Cycling offers a cost-effective and environmentally-friendly way to commute, a low-impact way to improve cardiovascular health, muscle strength and joint mobility, and can improve mental health.  

Injuries and deaths from cycling have declined in recent years. However, cyclists remain vulnerable road users, and cycling accidents can be serious, with head injuries being one of the main causes of death and life-changing injuries for cyclists involved in collisions. Yet the costs and designs of helmets vary widely and until now there have been no objective ratings about which helmets on sale in the UK offer cyclists the best protection.  

To produce the ranking, the Imperial team tested 30 of the most popular adult helmets on the market, all medium sized, based on a combination of in-lab testing, data from major retailers, and a survey of more than a thousand cyclists.    

All cycle helmets sold, and therefore all helmets tested in this study, must have passed regulatory standards to ensure they offer protection.  

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

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

Evidence from previous studies shows that head rotation is often associated with loss of consciousness and injuries deep in the brain that can be life-changing, for example triggering dementia.    

The overall risk was calculated as an average of the linear and the rotational risk, which assumes they have equal importance and presence in real-world casualties. However the researchers say the weighting of these risks should be adjusted in future as more data emerges on the distribution of these injuries and their consequences. 

Our research can now help consumers to make an informed choice when they buy a helmet. Dr Mazdak Ghajari Dyson School of Design Engineering

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

Senior 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 tremendously and we now know much more about how best to protect the human head from serious injury and injuries with long-term effects in a collision.  

“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.    

“Thanks to funding from the Road Safety Trust, our research can now help consumers to make an informed choice when they buy a helmet. We believe these ratings will lead to further improvements in helmet designs, providing better protection against a range of head and brain injuries if a cyclist is involved in a fall or collision.”

The Road Safety Trust has extended its funding for three years so that the team can apply its testing and rating techniques to children’s helmets as well as continuing to test the wide range of adult helmets available to buy.  

Ruth Purdie OBE, Chief Executive of The Road Safety Trust, which funded the research, said: “In the event of a collision, cycle helmets can play a vital role in preventing and reducing the severity of head injuries. 

“That’s why this new rating system is incredibly important. It will show riders which helmets offer the best protection, helping them to make better informed choices.”  

The research was funded by the Road Safety Trust and Innovate UK, part of UK Research and Innovation. 

“How Well Do Popular Bicycle Helmets Protect from Different Types of Head Injury?” by Baker et al., published 19 September 2024 in Annals of Biomedical Engineering. 

Main image: Shutterstock

Other images: Tomasz Tomaszewski

See the press release of this article