The arguments for and against the introduction and enforcement of bicycle helmet compulsion are not as straightforward as they may appear.
Pro-compulsion arguments and replies
Very many cyclists hit their heads
Every year many thousand persons report to hospitals with head wounds
Head injuries can have devastating effects, but the great majority are caused by falls or traffic injuries of a kind not suffered by cyclists. eg Motorcyclists are often involved in collisions with fast moving traffic, or slide at speed into kerbs or other road furniture. But these are fairly untypical cycle accidents, many of which involve crush or impact damage to the lower limbs.
Science says helmets are very effective
Several high-profile scientific reviews of the literature have concluded beyond doubt that cycling helmet show superior efficiency in reducing injuries. Template:Ref:Helmets for preventing head and facial injuries in bicyclists http://www.cochrane.org/reviews/en/ab001855.html
The reviews have only chosen a very narrow selection of articles on the subject and do not answer the criticism they have recieved. Also in the Cochrane case, the reviewers have themselves carried out the majority of the studies. The other review uses virtually the same narrow choice of studies.
Template:Ref:Curnow WJ., The Cochrane Collaboration and bicycle helmets. Accid Anal Prev. 2005 May;37(3):569-73. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list uids=15784212&dopt=Abstract
Cycling is much more dangerous than driving
Cyclists need protection just like car drivers
Protection is forced upon car-occupants
If a single life is saved by a helmet law it is worth it
Helmet compulsion for children even more pressing
Children have larger and heavier heads, relatively and therefore more easily get head injuries. Abilities to judge distances and speeds are also less than in adults.
True, but amongst children, neither is cycling a major cause of serious head injuries. On the other and physical exercise and freedom to explore is paramount to childrens deveolpement. The scientific evidence specifically on efficiency of helmets for children is no more conclusive than for adults or whole population studies. The frequently cited studies have so many errors. See the appendix of "Cycling and children and young people" by Tim Gill, for a treatise on children and helmet compulsion.
Contra-compulsion arguments and replies
No evident injury reduction in compulsion regions
Cycling has a very positive net health effect
Cycling is the most environmentally viable vehicle
Helmet compulsion reduces cycling
An Australian study, where compulsion has been introduced in some states but not in others, appears to show that compulsion reduces the number of people cycling, and particularly impacts the young and those taking up cycling generally.
Reduced cycling reduces safety in numbers
Helmet compulsion leads to risk compensation
The wearing of helmets appears to lead to cars taking less care and passing closer than they do to non-helmet wearing cyclists.
Helmets do not help against rotational forces
High speed head-injuries (such as those sometimes suffered by motorcyclists) are often caused by rotational forces on the head, This is much less significant in bicycle accidents.