Some caveats: Relative risk, Perceived risk,Helmet efficiency, Training Morten Lange, Landssamtök hjólreiðamanna 1 December 2009 Thanks to the authors for carrying out such a large review of the research literature on roads/facilities and cycling safety, and bringing forth some of the multitude of arguments for increased cycling for transport. I have several caveats though, many of which are shared with many that have put some long-term effort into understanding the issues and myths around cycling for transport. As such they should be known to the authors, as this is mostly readily available to those interested. This time around I'll mention them rather summarily : A. This article is not primarily of academic interest, rather the connection to key concerns in society is spelled out in the article, and the authors seem to hope to bring an important piece to a puzzle helping society to provide better for cyclists to improve their safety. So the preconceptions that the authors build on and the mindset in which the article will be read are important. B. Reading the introductory paragraphs it seems that the preconception of cycling being "inherently" dangerous is shared by the authors, as it will probably be by most readers. But to what extent does this preconception hold true ? The prime statistic that has been used to underpin the unsafe nature of cycling is to compare injuries pr. kilometre or mile with that of travelling in an car. But, as detailed in the 1999 EU booklet, "Cycling the way ahead for towns and cities", referring to various studies, this is misleading. As an example pedestrians have more deaths pr. kilometre than cyclists, and cyclists have a comparable number of deaths as do car occupants. Also on a per-trip basis. For certain age-groups, risk is much lower on bicycles than in cars. Another thing is this all "conveniently" excludes the question of the counterpart. Saying cycling is dangerous because cars drive fast and are large and heavy is like... ( Insert favourite victim-blaming phrase here ). Besides cyclists live longer than non-cyclists, according to several studies. That does not diminish the importance of improving safety for cyclists, but should put cause-and-effect pondering into perspective. Cyclists do not die because of cycling, or because of being vulnerable, they die because of excessive speeds of cars, taking size, weight manoeuvrability and lack of criminalisation of dangerous behaviour into account. Instead of takling of vulnerable road users, which sets them out as 2the others" we should talk of them as users of healthy means of transport. "Sound road users" ? C. The article gives the impressions that safety needs to be improved to increase cycling. The above should make the point that safety is not so bad. The difference is who is to blame for lack of safety. Unlike car users the threat comes from another group of users, that by the way also pollute, restrict access, and crave vast resources and areas of land. But clearly there is a problem of perceived risk. And clearly for many cyclists, especially novice ones, the feeling of being unsafe is a serious impediment. D. when talking of safety it is important to bear in mind that traing for cyclists, as well as years of experience both builds,trust, improves safety and inspires to growth in cycling which can bring about increased safety, not least through heightened awareness amongst motorists. E. The article seems to seek to shift focus in cycling safety from helmets etc to facilities. To shift focus from helmets is laudable, as their efficiencies have been much overstated, and are a hassle to many new and seasoned cyclists. And focus on helmets for cyclists generally constitute victim blaming in the case of collisions with cars. But in quote ii below the authors misrepresent the facts on helmet efficiency in the eyes of many experts. Anyone with god quality studies not mentioned in the Wikipedia article on bicycle helmets is encouraged to add references and a two-sentence synopsis in the appropriate paragraph. Probably unwittingly the authors of the present article (indirectly) misrepresent the main conclusion of one of the authors they cite. The conclusion of Dorothy Robinson, senior statistician, is not that helmets work, but that compulsion can reduce cycling. Her conclusion from several studies, are that helmet compulsion that brought about a very significant change in helmet usage in several jurisdictions, was not accompanied by any detectable improvement in the risk of serious head injuries. The reduction in cycling, following the enforcement of the helmet compulsion laws was however clear and significant. E. Finally I miss at least a short reference to the contrarian arguments to Pucher et al, that is the concept and the arguments for "Vehicular cycling", which appears as a word in the tables, but is not explained nor countered. See e.g John Franklin (Cyclecarft.co.uk) that wrote the book used for the national cycle training standard in the UK, John Forester etc. Best Regards, Morten Lange, MSc in Physics, Reykjavík, Iceland Relevant quotes from the article: i) "Bicyclists are vulnerable because they must frequently share the same infrastructure with motorized vehicles, and yet bicycles offer their users no physical protection in the event of a crash. In addition, the mass of a typical automobile is at least an order of magnitude greater than a bicycle plus its rider, and motorized vehicles have top speeds that are considerably faster than bicycles. As a result, bicycle riders who are involved in a crash are exposed to a much higher risk of injury compared to motor vehicle users (with the exception of motorcycle riders)." ii) "While helmets are effective in reducing the severity of head injuries, they do not address impacts to other parts of the body [16, 17]. More importantly, they do not prevent incidents from occurring in the first place , and legislating their use may even discourage cycling ." Competing interests None that fall into the traditional usage of this term. Some might consider cycling advocates to have competing interests, but I have seldom encountered a more honest, academically unbiased or altruistic group. They do however hold certain insights into the myths on cycling and the validity of some of the replies.