The cycle path debateEdit
The cycle path debate concerns the issues surrounding the provision and use of cycle paths. A cycle path or bike path is a track or road designated for use by cyclists that is physically separated from roads used by motor vehicles. It may be built for the purpose, or it may be an existing path marked as a cycle path. In some countries cycle paths are shared with pedestrians.
Cycle paths are widely used in parts of Europe, especially in towns in the Netherlands, and are also frequently seen on American college campuses. Most cycle paths are in urban areas; however, they can also be intended to link towns and cities, such as the National Cycle Network in Britain. Cycle paths are often made alongside canals or on the trackbed of disused railways. Cycle paths are essentially utilitarian in nature and they should not be confused with bicycle trails, off-road tracks used by recreational cyclists. Cycle paths should also not be confused with cycle lanes (or bike lanes) which are portions of roadway designated for bicycle use with a painted stripe.
Specific local cycle paths have been controversial amongst local residents, cyclists and transport planners. Some confident and experienced cyclists prefer to ride on the roadways, sharing them with motor traffic, instead of riding on a cycle path. In 2004, the state legislature of Iowa considered legislation that would have prohibited cycling on four-lane (dual carriageway) roads if the government decided that an adjacent parallel alternative route was readily available to cyclists.
The UK Department for Transport asserts that all types of cyclist will use high-quality well-maintained traffic-free routes if they are more direct than the equivalent on-road alternative and there are no personal security issues. The core of the cycle path debate is that very few cycle paths meet all these criteria.
The Department also usefully recognizes five types of cyclist:
- The fast commuter - confident in most on-road situations, and uses routes with significant traffic volumes if they are the most direct
- The utility cyclist - prefers separate paths at busy junctions and on roads carrying high-speed traffic
- The inexperienced cyclist - willing to sacrifice directness in terms of both distance and time, for a route with less traffic and more places to stop and rest
- Children - require segregated, direct routes from residential areas to schools, even where an on-road solution is available
- Users of wide or long equipment such as trailers, trailer-bikes, tandems, and tricycles.
In many countries it has proved very hard to design a suitable path to cater for all these types of users within available budgets.
Arguments in favour of cycle pathsEdit
- Most cyclist deaths are caused by a collision with a motor vehicle. Cycle paths segregate cyclists from motor vehicles and so save lives.
- Some people are frightened of cycling because of the perceived risk of collisions with motor vehicles. Segregated cycle paths may encourage these people to cycle.
- When riding on high speed carriageways, cyclists tend to hold up motor vehicles. Cycle paths segregate cyclists from motor vehicles and so allow the motor vehicles to go faster.
- A cycle path may offer a short cut not available to motor vehicles.
- Abandoned railway lines may be lost to development if they are not converted to new uses, such as cycle paths.
- Cycle paths have proved to be very popular where they are built. Especially among families riding with young children.
- A proper cycle path means cyclists are less likely to ride on paths made for pedestrians.
- Irrespective of the actual safety level, cycle paths offer superior riding comfort compared to on-road cycling. This is in part due to a higher perception of safety (which may be subjective) and in part because the cyclist only needs to watch out for motor vehicles at junctions, and isn't forced to constantly concentrate on potential dangers.
- Irrespective of the actual safety level, if cycle paths are percieved as safe, more people will cycle, and cycling will become safer through "safety in numbers".
Arguments against cycle pathsEdit
- The cycle path network is unlikely to become as extensive or interconnected as the road network; hence it is less convenient and will inevitably result in cyclists untrained in Effective Cycling being exposed to the road network eventually.
- By encouraging timid, untrained cyclists onto bicycles, cycle paths lure people into dangerous situations.
- The danger of collision with motor vehicles is highest at junctions. Most cycle paths have many junctions with roads, so the risk of collision may go up for users of cycle paths. Many junctions are very poorly designed.
- Removing cyclists from main roads allows motor vehicles to go faster; this causes more road traffic accidents in general.
- Cycle paths are rarely as well-constructed or maintained as roads. They are often narrower than roads, have tighter corners, worse lighting, poorer surfaces, and more obstacles.
- The maximum safe speed on a cycle path is usually lower than on a road; journeys on cycle paths take longer than on roads.
- Generally the start and end of any cyclist's journey is on the road system, so using cycle paths often involves a diversion.
- The majority of injuries to cyclists are not caused by collisions with motor vehicles. So moving cyclists from well-constructed roads to poorly-constructed paths may result in more injuries.
- Cyclists may not share facilities well with pedestrians (cyclists cannot maneuver as deftly as pedestrians, and so can easily travel too fast to avoid a collision) which increases risk to both parties.
- Cycle paths may be less frequently cleaned of debris and snow/ice than roads.
- Sidewalks which have been later re-designated as cycle paths may contain various obstructions including bus stops, pillar boxes and telecommunications cabinets. This can be a particular problem in the UK.
- Converting cycling trips from road to path may decrease general safety for road cyclists (the authors of some studies have concluded that the average rate of injuries per road cyclist varies inversely with the number of cyclists on the roads).
- In some countries the introduction of segregated facilities may be a first step towards the banning of cycling on roads.
Many advocates now talk of recreational trails, shared-use paths, or community paths, recognizing that avid cyclists find cycle paths less than ideal, while they have become very popular for other uses, including walking, jogging, inline skating, wheelchair excursions, cross-country skiing as well as more casual cycling.
- City of Chicago Bike Lane Design Guide
- Why have shoulders and/or bike lanes? - Oregon Department of Transportation
- Engineering and Planning : Bike Lanes - Bicycle Transportation Institute
- Bicycle Blunders: Blunders in Planning & Engineering - LAB Reform
- A critical look at bike facilities including bike lanes - John S. Allen
- A critique on a sidepath-style bike lane design in Cambridge, Massachusetts
- Analysis of the major arguments about bike lanes - John Forester
- UK Department for Transport, Local Transport Notes
- Study on the causes of bicycle and pedestrian injuries - Jane C. Stutts and William W. Hunter
The helmet debateEdit
There is a long-running argument over the use, promotion and compulsion of cycle helmets. Most heated controversy surrounds laws making helmet use compulsory, particularly regarding the substantial disparity between claimed injury savings in small-scale prospective studies (e.g. Thompson, Rivara and Thompson, 1989) and later, more comprehensive studies, particularly from jurisdictions which have used compulsion to substantially raise helmet use over a very short period. Helmet use in New Zealand, for example, rose from 43% to over 95% in under three years, with no measurable change in head injury rates (Scuffham, 1997).
Controversy is fuelled by support given to the pro-compulsion movement by Bell Sports in particular, and by the fact that many of the most vocal proponents of helmets are not themselves cyclists.
Overall, most cycling groups are opposed to mandatory helmet use, partly on grounds of equitability (cyclists are more often the victims in crashes than the cause) but largely because of the deterrent effect of laws on levels of cycling. Cycling gets safer the more people who do it.
Do helmets reduce fatalities or serious injuries?Edit
It is often implied that wearing a helmet is the first, best thing a cyclist can do to ensure their safety. In general, analyses of the relative merits of different bike safety interventions put helmets last, because no helmet will reduce the probability of crashing (indeed there are credible suggestions that helmets may increase this likelihood). Proactive measures including bike maintenance and riding skills are far more important. Although the link is not directly causal it is noticeable that the countries with the best cycle safety records (Denmark and the Netherlands) have among the lowest levels of helmet use. Their bicycle safety record is attributable to improved education, separation from motor traffic (but see the entry on segregated facilities) and, most importantly, public awareness and understanding of cyclists.
The best scientific evidence on the effectiveness of helmets would be derived from randomized controlled trials, in which some cyclists were randomly assigned to wear helmets and others not. No such trials have been done. The available evidence comes from two main types of observational study. The first is case-control studies, in which cyclists who have injured their heads ("cases"), and cyclists who have not ("controls"), are asked whether they were wearing a helmet at the time of their crash. Several such  case-control studies have been done. They consistently find that cases report a lower rate of helmet-wearing than controls. This has been taken as strong evidence that cycle helmets are beneficial in a crash and that all cyclists should be compelled to wear them. These studies have a serious flaw; people exaggerate their use of cycle helmets, and this exaggeration may only apply to people who have not hit their heads . If this is true, these studies would be valueless; they would incorrectly indicate benefit from helmet wearing. Other criticisms apply to some or all of the available case-control studies. For example, a study by Thompson, Rivara, and Thompson reported an 85% reduction in the risk of head injury by using a helmet. It used a control group which reported a voluntary helmet use rate almost 10 times higher than the general population. Voluntary helmet users are more cautious than the general bike riding population . They would be expected to have different sorts of injury even without the use of helmets, and this particular study, the source of the most optimistic claims for helmet effectiveness, is weaker than most. Many more criticisms have also been levelled at the study.  
Other studies have looked at the results of laws compelling cyclists to wear helmets. Many such laws have been passed in various areas. Only four such areas have both enforced these laws and produced good quality data on the results . These data, from areas where helmet wearing increased by at least 40%, show no obvious effect on the proportion of head injuries. These studies are based on observations of helmet wearing by third parties, and are more likely to be valid than the case-control studies. They have in turn been attacked.
Other researchers  in the University of Western Australia Public Health Department in the late 1990s have suggested that there had been a small, but statistically significant reduction in head injuries to Western Australian cyclists between 1973 and 1998, during which period helmet use rose from zero to around 85%. Cycle helmets were made compulsory in 1992. The study compared the percentage of head injuries recorded among cyclists and pedestrians in road traffic accidents. After the law, there were fewer cyclists in any age group. Child cyclists are more likely to bump their heads, and their numbers declined more than adults. A reduced proportion of cyclists in the age group most likely to bump their heads could account for all the apparent, small, protective effect of helmets in this study. A similar study was conducted in Otago, New Zealand. (Scuffham, Alsop, Cryer, Langley 2003)
The conflicting evidence has led to widespread and longstanding controversy. Various organizations have taken up definite positions on the issue, not always based on a full review of the evidence. For example, the British Medical Association used to be against helmet compulsion, following an extensive review of the evidence in 1999. In late 2004 the BMA's Board of Science and Education adopted a 'position' calling on the UK government to introduce cycle helmet legislation, and this was confirmed at the 2005 Annual Representative Meeting following fifteen minutes of debate(transcript). The BMA's new position may use statistics provided by the British political lobby group, the Bicycle Helmet Initiative Trust. Several provably wrong figures were removed after initial publication, but the supposed review of evidence is still distorted, excluding not only references included in the 1999 BMA study, but the 1999 study itself.
However, the former UK Minister for Road Safety, Mr David Jamieson MP, has acknowledged that he knows of no evidence linking increasing helmet use with reduced severity, or risk, of head injury to the cyclist population. This contrasts with jurisdictions which have made bicycle helmets compulsory, where the utility of helmets and helmet laws has been vigorously asserted.
Reduction in bicycle participationEdit
Mandatory bicycle helmet laws may lead to a reduction in the number of cyclists. The reduction in the number of cyclists may have a more negative impact on the health of a population than would have arisen from the head injuries that would have resulted from not using helmets since the reduction in injuries is apparently so small. The long term health benefits of bicycle use are well established so any reduction in bicycle activity will likely have a negative impact on the overall health of a population.
Arguably, even helmet promotion or high levels of helmet use by utility cyclists will deter non-cyclists by reinforcing the misconception that bicycling is a lot more dangerous than walking or driving. This reduction of cycle use directly imposes increased risk on cyclists that continue to ride, due to the now well established "safety in numbers" effect. However, by statistics, cycling in general is safe compared to almost any other form of transportation. Only airline travel is safer per million exposure hours according to one American study. 
Helmets and increased risk of injuryEdit
Some studies have even suggested that helmets increase risk. Although the head injury rate in the US rose by 40% as helmet use rose from 18% to 50%, this does not necessarily mean that helmets themselves increase risk. In fact, a range of theories exist to explain the observed disparity, including:
- Risk compensation: helmeted cyclists may ride less carefully; this is well supported by evidence for other road safety interventions such as seat belts and antilock brakes.
- Poor fitting: 96% of helmets not fitted correctly and incorrectly fitted helmets reportedly increase risk by a factor of 3.
- Sampling bias in prospective studies: voluntary wearers may be more risk averse, skewing the results.
No research has yet been published which adequately addresses the reasons for the disparity, so while the disparity itself is solid fact based on robust data collected and published by governments, the above reasons are speculative and undoubtedly not exhaustive.
Recent research on brain injury adds further confusion, suggesting that the major causes of permanent intellectual disablement and death may well be torsional forces leading to diffuse axonal injury, a form of injury which helmets cannot mitigate. Helmets can increase the rotational force acting on the head by virtue of the longer distance between the extremities of the helmet and the centre of the cervical spine, compared to the head without a helmet. In addition, the hardness of the typical helmet may accentuate this problem. For example, if a person is sliding and the helmet strikes an object, the linear movement may be converted into rotational force about the spine.
Some argue that the helmets that are currently on the market are not designed suitably to make a large reduction in fatalities for the types of injuries they are supposed to protect against. However, measures required to improve helmets would make the helmets commercial failures. Helmets designed to a higher standard have not sold well, while helmets designed to even lower standards have sold well.  Some helmets on the market do not even meet basic requirements.
Use, promotion, compulsionEdit
It is plausible that if a rider chooses to use a helmet, and maintains their safe cycling habits, they should be moderately safer than if they chose not to wear a helmet, although risk compensation theory states that an intervention as obtrusive as a helmet will very likely affect riding practice at the subconscious level. Wearing and non-wearing are both, therefore, sound choices, supportable from the available evidence. A person refusing to ride without one probably overestimates either the risks of cycling or the protective effect of helmets.
Promotion of helmets is somewhat more problematic. Helmet promoters routinely make claims which manufacturers cannot, due to advertising restrictions. Promotion campaigns are often supported and/or funded by manufacturers. Bell, one major helmet manufacturer, supports both helmet promotion and, through its Legislative Assistance Programme, laws. The major problem with helmet promotion, from the point of view of cycle activists, is that in order to present the idea of a "problem" to match the solution they present, promoters tend to overstate the dangers of cycling. Cycling is, according to the evidence, no more dangerous than being a pedestrian. In fact, helmet compulsion in cars would be far more effective at reducing injuries than on bicycles. 
Some bicycle activists complain that focus on helmets diverts attention from other issues which are much more important for improving bicycle safety, such as training, roadcraft, and bicycle maintenance. Of 28 publicly funded cycle safety interventions listed in a report in 2002, 24 were helmet promotions. For context, one evaluation of the relative merits of different cycle safety interventions estimated that 27% of cyclist casualties could be prevented by various measures, of which just 1% could be achieved through a combination of bicycle engineering and helmet use.
Data from around the world shows that despite the optimistic claims for injury reduction made by their proponents, no helmet law currently in force has led to a measurable reduction in cyclist head injury rates. There are a number of plausible explanations for this:
- the studies on which the laws are founded mainly compare those who choose to wear helmets with those who do not; forcing a cyclist to wear a helmet will not make them behave like the kind of cyclist who wears one by choice
- helmets are not designed to withstand motor vehicle impacts, but these account for most serious and almost all fatal cyclist injuries
- governments do not tend to measure minor injury rates; any protective device would be expected to be much more effective against minor injuries, rapidly tailing off with severity - although a few studies do claim that cycle helmets are more effective against serious than against minor injuries, it is more likely that the efficacy figures cited in advance are against a type of injury which subsequent statistics will not measure
- helmet laws tend to deter cycling; there is good evidence that cycling becomes safer the more people who do it.
Overall, cycling is beneficial to health - the benefits outweigh the risks by up to 20:1. Anything which jeopardises that benefit must be carefully weighed to ensure it is likely to achieve some meaningful benefit in turn. Thus far, no helmet law has been shown to do that.
Cycling as a dangerous activity Edit
A further source of contention is the apparent arbitrariness of cycle helmet promotion and/or compulsion. Ordinary cycling is not demonstrably more dangerous than walking or driving, yet no country promotes helmets for either of these modes. Cycle helmet use correlates inversely with the level of cycling in a given country. Official zeal for cycle helmets is greatest where cycling is a minority activity.
Detailed analysis of hospital admissions data also fails to support the idea that cycling is unusually dangerous: a study in the UK found that the proportion of cyclist injuries which are head injuries is lower than the proportion for pedestrians.
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