The Potential for Cycle Helmets to Prevent Injury: A Review of the Evidence

There has been much debate in literature and elsewhere regarding cycle helmets and their potential to prevent injury.

This cycle helmet safety research report was commissioned to provide a comprehensive review of the effectiveness of cycle helmets in the event of an on-road accident, building on previous work undertaken for the Department for Transport (Towner et al., 2002).

The programme of work evaluates the effectiveness of cycle helmets from several perspectives, including a review of current test standards; a biomechanical investigation of their potential limitations; a review of recent literature; and finally an assessment of the casualties that could be prevented if cycle helmets were more widely used.

The report concludes that, assuming that cycle helmets are a good fit and worn correctly, they should be effective at reducing the risk of head injury, in particular cranium fracture, scalp injury and intracranial (brain) injury.

It suggests that cycle helmets would be expected to be effective in a range of accident conditions, particularly:
• The most common accidents that do not involve a collision with another vehicle, often simple falls or tumbles over the handlebars.
• When the mechanism of injury involves another vehicle glancing the cyclist or tipping them over causing their head to strike the ground.

• A specialist biomechanical assessment of over 100 police forensic cyclist fatality reports predicted that between 10 and 16% could have been prevented if they had worn an appropriate cycle helmet.

• Of the on-road serious cyclist casualties admitted to hospital in England (HES database):
• 10% suffered injuries of a type and to a part of the head that a cycle helmet may have mitigated or prevented.
• 20% suffered ‘open wounds to the head’, some of which are likely to have been to a part of the head that a cycle helmet may have mitigated or prevented.

Cycle helmets would be expected to be particularly effective for children, because:
• The European Standard (EN 1078) impact tests and requirements are the same for adult and child cycle helmets – both use a 1.5 m drop height test.
• Given that younger children are shorter than older children and adults, their head height would be within the drop height used in impact tests, so a greater proportion of single-vehicle accidents are likely to be covered by the standard for children.

No evidence was found for an increased risk of rotational head injury with a helmet compared to without a helmet.

In the literature reviewed, there is a difference between hospital-based studies, which tend to show a significant protective effect from cycle helmets, and population studies, which tend to show a lower, or no, effect. Some of the reasons behind this were due to:
• The lack of appropriateness of the control groups used.
• Limitations in the available data, such as knowledge of helmet use and type of head injury.