Bicycle Helmet Use vs. No Helmet: Key Statistics 2025

Injury Risk and Severity

A robust body of research shows helmets provide a substantial protective benefit in crashes. A 2017 meta-analysis of 40 studies (with over 64,000 cyclists) concluded that helmet use is associated with a 51% lower risk of head injury​ (source).

Importantly, the protection is even greater for severe injuries – the odds of a serious head injury are reduced by about 69% with a helmet, and the odds of a fatal head injury are reduced by about 65% (source).​

In practical terms, this means the likelihood of a life-threatening head trauma is cut by more than half when a cyclist is wearing a helmet. Notably, the same meta-analysis found no increase in neck injuries with helmet use​ (source).

(disproving a common myth that helmets might cause neck harm in a crash).

Helmets also clearly mitigate head injuries in real-world hospital data. A large-scale analysis published in the American Journal of Surgery looked at 6,267 cyclists in the U.S. trauma registry and found only 25% were wearing helmets at the time of injury​ (source).

The outcomes for that minority of helmeted riders were significantly better: they had 51% lower odds of severe traumatic brain injury and 44% lower odds of death compared to non-helmeted riders​. They also had 31% lower odds of facial fractures​ (source).

Another study of 76,032 cyclists with head/neck injuries reported similar findings – helmet wearers experienced less severe injuries, shorter hospital stays, and lower mortality than non-wearers​ (source).

These statistics reinforce that, in the event of a crash, a helmet can greatly reduce the severity of head trauma.

Head Injuries and Fatalities

Head injuries are the leading cause of cyclist deaths, and helmet use directly addresses this risk. The U.S. National Transportation Safety Board has noted that head injury is the primary cause of fatal cycling injuries​ ntsb.gov

. By absorbing impact energy and shielding the skull, helmets help prevent the kind of catastrophic brain injuries most likely to be fatal​ cpsc.gov

​One estimate from a global Cochrane review found that helmets may provide a 63–88% reduction in the risk of head, brain, and severe brain injury for cyclists of all ages​ (source)

While the exact percentage varies by study, the consensus is that helmets significantly reduce head injury risk.

It’s also illustrative to compare the share of serious injuries among helmeted vs. unhelmeted riders. A 2024 Norwegian trauma-center study found that among cyclists admitted to the hospital, serious head injuries occurred in only 22% of helmeted riders, compared to 38% of non-helmeted riders​ (source)

In other words, unhelmeted cyclists were far more likely to sustain severe head trauma. Likewise, the need for neurosurgery (such as to relieve brain bleeding) was 64% less common in helmet wearers​. Even the 30-day mortality in that study trended lower for helmeted cyclists (1.5% vs 2.9% for non-helmeted)​ (source)

 

The table below summarises how helmet use correlates with injury outcomes in select studies:

 

Table: Examples of injury outcomes with vs. without bicycle helmets. “–%” entries indicate the reduction in odds/likelihood for helmeted riders relative to non-helmeted riders.

As the table shows, multiple independent analyses converge on the finding that helmets typically reduce head injury odds by about half, and even more for severe and fatal head injuries. Non-helmeted riders, by contrast, consistently show higher rates of serious trauma.

Fatal Crashes

The relationship between helmet non-use and fatal outcomes is stark. We already noted that one study found the risk of a fatal head injury was ~3 times higher without a helmet (source).

Another frequently cited statistic (from older U.S. data) states that non-helmeted riders are 14 times more likely to be involved in a fatal crash than helmeted riders (source). This 14× figure, while dramatic, comes from aggregated risk data, including many child cyclists. It underscores how lethal a crash can be for those without head protection.

By contrast, safe cycling advocates estimate that 75% of bicyclist fatalities could be prevented by universal helmet use (source), especially among children (source).

In the pediatric population, not wearing a helmet is associated with a 3-fold higher risk of serious head injury compared to helmeted children (source). These numbers highlight that many of the worst cycling outcomes (fatalities and severe brain injuries) disproportionately occur among riders without helmets.

Prevalence of Head Injuries

Cycling accidents result in tens of thousands of head injuries each year. In the United States alone, emergency departments treat an estimated 80,000+ cycling-related head injuries annually (source).

About one-third of all non-fatal cycling injuries are head injuries, including concussions and skull fractures (source). Because head injuries can have lifelong consequences (brain damage, cognitive impairment, etc.), preventing even a fraction of them through helmet use can have significant public health benefits.

The U.S. Consumer Product Safety Commission emphasizes that helmets absorb impact energy and can prevent more serious injuries to the brain (source). No helmet can guarantee a rider’s safety or prevent every concussion, but the consensus of data is that wearing one greatly improves your odds of avoiding severe head harm in a crash.

Limitations

It’s important to acknowledge that helmets address injury severity, not the occurrence of crashes themselves—they are a last line of defense. Other factors like speed, collision type, and vehicle involvement also influence outcomes.

Some analyses note a correlation between higher helmet use and higher perceived danger (i.e., in places where cycling is more dangerous, more people wear helmets) (source). Thus, raw comparisons can be confounded—a country or city could have lots of helmets and lots of crashes if the infrastructure is poor.

Nonetheless, when a crash does happen, the scientific evidence strongly indicates you’re better off wearing a helmet than not.

 

Country-Specific Data

 

United States

More than 1,000 cyclists die each year in the US, and around 350,000 are treated in emergency departments for cycling injuries. (Source)

United Kingdom

The UK sees about 100 cyclist fatalities per year, with thousands of serious injuries. (Source)

Australia

Helmet use in Australia increased from ~37% to 82% post-law, and head injuries fell about 29% in New South Wales after implementation. (Source)

Ireland

About 62% of Irish cyclists wear helmets. Ireland does not have a mandatory helmet law, but cycling safety campaigns encourage helmet use. (Source)

European Union

Helmet use in Europe varies widely, with rates as low as 5% in the Netherlands but over 40% in Sweden. (Source)

Best Bicycle Helmets for Safety

Helmets with MIPS (Multi-Directional Impact Protection System) reduce concussion risk. (Source)

Some top-rated helmets include the Giro Aries Spherical, Specialized Tactic 4, and Bontrager Charge WaveCel. (Source)

 

Final Words on Helmet use

As you can see, the data is clear. Wearing a helmet makes a massive difference.

You greatly improves your chances of avoiding serious head injury or death in a crash. At the same time, the safest cycling environments are those that prevent crashes in the first place, helmet or not.

For this reason, dedicated cycle paths like the South East Greenway, make all the difference statistically.

That said, always wear your helmet.

Safe cycling!

Prepared on March 1, 2025. All data are the most recent available as of this date.