Related links:
Helmet Sound Bites
Conventional Beliefs about Helmets
Meditations on the Helmet Wars
URLs for Reference

Public Perception and Reality

In the past year and a half, I have been witness to an extraordinary event: An analysis based on demonstrably incorrect data and flawed logic has achieved the status of conventional wisdom.

-- Jonathan Koomey of the End-Use Forecasting Group at Lawrence Berkeley National Laboratories
(quoted in Turn off the Internet! by Katharine Mieszkowski, Salon online magazine article about the great spin control campaign underway to turn California's electricity crisis into PR for the coal industry.)

This kind of thing happens all the time, alas. John Stossel goes on the air and declares that "research shows" that organic foods are more dangerous to your health than foods grown with pesticides. There's no basis in fact for his remarks, yet it makes a great soundbite and gets repeated ad nauseam -- if repeated loudly enough and often enough, with no countervailing information, it becomes "truth".

Just ask anyone who listens to Rush :-)

Unfortunately, I feel that the contemporary obsession with bike helmets as the primary or only criterion for cyclist safety is equally fictitious. The history of this social/legislative trend is pretty strange, and the beliefs which underpin it are in many cases not well substantiated. In this document I try to list the assumptions which underlie the passionate belief of many Americans (cyclists and non-cyclists) that "only an idiot would not wear a helmet", and ask whether these assumptions can be proven or disproven, or whether they are merely a matter of personal opinion.

Some Common Beliefs about Bike Helmets

  1. Cycling is dangerous therefore cyclists should wear appropriate protective clothing.
    (Corollary:) Mandatory helmet laws will save many lives each year.
  2. A bike helmet will ensure your safety.
  3. Helmetizing might not be sure to help, but it can't hurt.
  4. Modern bike helmets are better.
  5. Mandated helmets are no less reasonable than mandated seat belts.
  6. Mandatory helmeting is a socially progressive move and the US would be reactionary not to adopt it.
  7. Mandatory helmeting is an important public health strategy
  8. Who cares if a few recreational cyclists have to wear helmets?
  9. But It's Just Common Sense!

How Dangerous is Cycling?

On the whole, cycling is no more dangerous as driving a car, per hour of exposure. In city traffic, bikes and cars achieve about the same average speed -- 12 to 15 MPH -- so it's appropriate to compare hourly risk rates.

In traffic accident statistics from the US and Europe, both pedestrians and car drivers in urban settings are consistently shown to be at higher risk than cyclists. The stock road bike is actually the safest as well as the most efficient way to get around a city.

Deaths in bike accidents in the US average about 900 per year. For a sense of risk scale: mortality from cigarette smoking is about 400,000 per year; from automobile accidents about 40,000 per year; from skin cancer about 10,000 per year. If we add the collateral damage from automobile driving (about 30,000 dead per year from smog-related diseases), cars kill something like 70 times more people than bikes. In point of fact, most fatal cycle "accidents" are actually collisions with cars.

Moreover, very few bike accidents kill anyone other than the cyclist him/herself. Many if not most car accidents kill people other than the driver. Expert estimates of the share of cycle deaths that result from head trauma vary wildly from 5 percent to 85 percent (see a quick summary of the statistical debate courtesy of Daniel Convissor).

Whether 5 or even 85 percent of 900 deaths per annum -- out of a population of over 250 million -- strikes you as "many" (when compared to other major health hazards which don't elicit legal sanctions) is a matter of opinion. The British Medical Association maintains that the health benefits of cycling outweigh the risks by 20 to 1!

How Effective is a Helmet in Traffic?

Those who die while riding bicycles on roadways are mostly killed by automobiles, i.e. by high-speed impact with heavy, armoured vehicles -- not by simple falls onto hard surfaces.

Fault, in terms of violation of traffic law, is not always on the driver's side. Often (especially younger) cyclists ride on sidewalks (as they have been wrongly taught to do in many cases), fail to stop at stop signs, ride the wrong way, and otherwise surprise and confuse car drivers.

Careless car drivers, however, also claim the lives of many cyclists and pedestrians. For reference, here are some good links about automobile-imposed risks.

What does this mean when we consider helmets? It means that the maximum risk to a cyclist is being struck by a car in traffic. But bike helmets are rated for forces equivalent to falling from bikes, not for the forces involved in being struck by a car at road speed.

Furthermore, as far as I can make out, most helmets are rated very honestly by their manufacturers as single-impact devices. On the first major impact, the helmet absorbs the shock; in doing so, the foam protective layer shatters. You are advised to replace it after any serious impact, for this reason. The bad news is that serious encounters with automobiles (the biggest danger for adult cyclists) often involve two impacts: one when the car hits you, and a second one as you are thrown, or fall, to the ground. Bike helmets are not engineered for two major impacts in a row, even though this is the type of collision (at speed) most likely to cause fatality or major injury.

"A Bell Sport 2000 motorcycle helmet weighs 1700 grams and a Giro Ventoux bicycle helmet weighs 200 grams. Yet the motorcycle helmet only protects against a 12mph impact." So writes Chris Gillham, tireless activist opposing Western Australia's MHL.

If helmets significantly reduced trauma and fatality rates, one would think that motorcycle helmets in particular (being large, solid, and much more strongly built than bike helmets) would have a consistent net positive influence in US states with "lid laws". Such is not the case: "Relative to the number of registered motorcycles, states with mandatory helmet laws had 12.5% more accidents and 2.3% more fatalities than free choice states for the 14 year period 1977-90. (Accident and Fatality Statistics, analyzed by A.R. Mackenzie, M.D.) Motorcycle Helmet Law Repeal Site

If large, clunky, "serious" motorcycle helmets don't reduce motorcycle fatalities when mandated by the state, why would we expect small, flimsy bike helmets to help? In the real world, they have not. Despite the adoption of bike helmets due to trendiness and advertising in some areas, and the forcible marketing of helmets by state decree in others, there is no statistically meaningful connection between adult cyclist fatality and trauma rates and the wearing or not wearing of helmets.

Great claims have been made for the reduction of juvenile cyclist traffic fatalities in the US since helmets became popular, but these proponents conveniently ignore the fact that juvenile pedestrian fatalities declined similarly over the same period: and in each case the simple explanation is that after the scare campaigns about traffic "safety," many parents started forbidding their kids to walk or bike anywhere. Oddly enough [Editorial grin] during the same years US health officials have been appalled by a new trend in reduced fitness among children -- gee, I wonder how that happened?

When it comes right down to it, safety for cyclists cannot be achieved by any means as easy as buying a plastic product and putting it on your head. It takes social engineering to make our streets safe, and it takes skill and alertness (and obedience to traffic law) to operate a bicycle safely. Cyclists need to be trained from childhood to obey traffic laws, and (sorry folks) we need to be ticketed for our infractions; and motor vehicles need to be slowed down and ticketed for unsafe driving.

A bike helmet is not likely to save your life when you collide with a SUV at 30 mph. Says Malcom Wardlaw (private correspondence): "It is interesting to read through the response to my paper from cyclists who wear helmets. Now they must admit that a helmet won't do them any good in a crash with a car, they claim they wear one because they might fall off, or a nasty small boy might throw something at them!"

How Harmless is Mandatory Helmeting?

The primary effect of the unremitting campaign to "dangerize" cycling (besides increasing helmet sales and plastics industry revenues) is to make more and more people afraid to ride a bike, so that they choose to drive instead -- exposing themselves to at least as much real danger.

But there is also a feedback loop: their fear-driven preference for automotive transport then increases traffic congestion, thus raising the risk to pedestrians, other drivers, and cyclists. The fewer cyclists there are on the roads, the more dangerous it is for those who continue to ride.

Children who are forcibly helmetized can develop a distaste for cycling and a longing to "grow up and get a car" so they don't have to wear a helmet all the time. Teaching the next generation that bikes are dangerous and cars are safe (and cool) strikes me as a form of harm. Certainly, teaching children that a helmet is all they need to be safe does considerable harm, encouraging reckless riding and contempt for traffic law. And I mentioned above that kids who never walk or bike anywhere do not grow up as strong and fit as kids who have more individual, active mobility.

The design flaws of the modern "aero" helmets may or may not contribute to cyclist injury; as far as I know, no one is bothering to investigate this. Civic and regional agencies often feel that by enforcing helmet use they have done all that is necessary; they then feel free to neglect other, far more important bike safety issues and continue to prioritize and facilitate auto use. As one gentleman from Austin put it, they want to make it safer for cyclists to crash, not safer for cyclists to ride.

As Wardlaw put it in his Dec 2000 paper in the British Medical Journal: "Cyclists don't need helmets -- they need priority." Instead of getting priority (as a safe, non-polluting, congestion-easing, socially responsible form of daily transportation), cyclists are stigmatized as a bunch of daredevils indulging in a dangerous and impractical "sport". The helmet hysteria that has been stirred up over the last quarter century has contributed greatly to this stigmatization and false characterization of cycling, and this in turn has caused harm by discouraging cycling and promoting the automobile.

Conflicting Design Requirements

Because of cyclists' reasonable complaints about heat exhaustion, sweat, weight, and so forth, helmet designs have evolved from the spherical motorcycle type to the modern "cute little hat" aero type with pointed ends and lots of vents. The new lightweight hats are more comfortable, but even dedicated helmet law advocates caution that they are less effective than the full head armor; the pointy ends may even be hazardous in a skidding fall.

If the projecting ends or visor catch on anything, the cyclist's head can be rapidly twisted, causing neck injury. This kind of rapid slewing and twisting motion is associated with brain injury as well -- more closely, in fact, than the stereotypical "bonk" on the skull. What does the damage is sloshing the brain around in its casing; only in very extreme cases is a human skull breached by blunt or sharp objects in collision. The literature that comes with a new bike helmet, if you read the fine print, actually admits the risk of torsion injuries and disclaims all manufacturer responsibility!

The helmet propaganda campaign has led to a vastly increased demand for helmets, but the discomfort and impracticality of any really effective helmet (recall the efficacy of motorcycle helmets discussed above) has led to the acceptance of relatively dysfunctional designs. People are fooled into thinking that weakened designs are "improved" and thus place an exaggerated trust in these helmets.

Just Like Seatbelts?

Helmet law proponents often argue that people were unhappy with seatbelt laws originally, yet the safety standards in cars today are a good thing; therefore it is foolish or "juvenile" to resist helmetization. In fact, enthusiasm for helmet laws did follow on the visible success of seatbelt laws in reducing automotive fatalities.

Let us take a moment to examine this comparison. The seat belt laws were inspired by safety activists like Ralph Nader. They were responding to the fact that auto manufacturers were selling a product (cars) that was manifestly unsafe, and not adequately warning consumers of the risks involved in driving a car. It was a consumer product safety issue: a vendor was selling an unsafe product.

Seat belts are tested fairly rigorously using crash-test dummies, which simulate the actual stresses on whole human bodies from automobile impacts. Helmets (both cycle and motorcycle) are tested by being dropped a few feet onto a hard surface, directly onto their strongest point (the crown), with a metal weight and a g-meter inside. There is no attempt to simulate the real weight of a human body, or the real structure of a human skull and neck, in a real fall.

Note that the bike helmet laws and helmet propmotion are mostly intended to protect cyclists not against a fundamentally unsafe product that they themselves bought (the bicycle) -- no matter how often the Bikes Are Dangerous mantra is repeated, the statistics don't bear it out. The helmet is being promoted to protect cyclists (inadequately) against cars.

Thus the two laws are quite different in nature. In one instance, the risk to the car driver is imposed by their own choice to own and drive a car, and the law forces the manufacturer and user to mitigate as far as possible the product's risk. In the other case, the cyclist is exposed to a risk (from cars) that is not a direct consequence of their own choice (to own and ride a bicycle); yet it is the cyclist who is being blamed for the risk, and expected to spend extra money, submit to restrictive legislation, etc.

The automobile is inherently unsafe, due to its weight and speed and the advanced skills needed to drive expertly; the average bicycle is only considered unsafe because it has to share the road with dangerous cars.

Consider for a moment the problem of theft. Is the solution to the prevalence of thieves in our society to pass laws mandating burglar alarms and gun ownership? Should homeowners be ticketed for not having a burglar alarm? Or should we try to reduce the number of burglars by dissuasion and by improving social equity? If there is gun violence in our schools, should we mandate the wearing of Kevlar vests by all school children? Or should we try to remove the danger, rather than penalizing the innocent? Which is more reasonable?

Driving a car is dangerous all by itself, to the driver, to other road users, and to all oxygen-breathing life forms; riding a bike (for normal daily purposes, not extreme sports) is dangerous only because of the overpopulation of cars and the special privileges given to car drivers.

And while we're on the subject of seatbelts, there may be some more disturbing news to consider. There's some evidence that mandatory seatbelt installation and use for drivers actually made our roads more dangerous for everyone else! This depressing theory is explored by Shane Foran in commentary submitted to the British Medical Journal.

Socially Progressive?

In the Netherlands and Denmark, commonly considered the most advanced and liberal countries in Europe, the solution to bicycle safety has been to tame traffic by restricting auto access to residential and shopping districts, reducing traffic speeds, strongly supporting public transit, and encouraging and subsidizing bike riding. In the Netherlands, bike helmets are not only not mandated, but US cyclists who visit there and ride helmeted cause considerable public amusement. In the Netherlands, from 40 to 50 percent of the population commutes to work on bicycles.

The notion that Americans think cycling is dangerous is quite funny to Dutch cyclists, who are well aware of America's pathetic record on gun control! Despite all this "dangerous" unhelmeted riding, the bike safety record of the Netherlands is exemplary, with the lowest mortality rate of any industrialized bike-riding nation. This is because they have addressed the real problem: the cars.

Forcing helmets on cyclists is not a progressive move, but a reactionary move that perpetuates the special privileges accorded to the automobile industry and to automobile users. "Dangerizing" bikes distracts public attention from the many dangers of automobile travel. This privileging of the automobile is maintained at tremendous environmental and social cost.

There are three groups of people who really benefit from bike helmet laws and the helmet scare campaigns. The auto industry sells more cars to people who are afraid of cycling, and the oil companies sell more petrol. The auto/oil lobby wins. The insurance industry gets to deny more compensation claims: in a helmet-crazed society, any cyclist who has the bad luck to be struck by a careless driver while not helmeted can pretty much count on being blamed for his/her own injuries by police, media, and courts ... even if the driver was in violation of the vehicle code at the time of the accident. So the insurance company wins. And of course, the plastics industry and the helmet manufacturers win -- they get to sell millions of units to a captive market, in countries with MHLs, and to a scared, insecure consumer base even in countries without MHLs.

There's nothing progressive about an aggressive marketing campaign that plays on public fear, spreads disinformation, perpetuates car-dependency, promotes injustice, and lines the already plush pockets of the petroplastic, insurance, and auto industries.

Do Helmet Laws Promote Public Health?

One of the leading health problems in the US (second to tobacco addiction) is poor cardiovascular fitness. One of the root causes of poor fitness is a life with no regular exercise, largely created or even enforced by total automobile dependence. Daily bike riding has been estimated to add as much as 10 years to a person's life span.

Contrary to the anti-bicycle propaganda produced by the helmet law faction, riding a bicycle has a lifetime health impact that is far more positive than negative. A far-seeing public health policy would encourage Americans to ride their bikes every day, and would start to work on dismantling our automotive prison society in which people are literally coerced into owning and driving cars.

When all-ages helmet laws were enforced in Western Australia, bike ridership declined considerably and has not yet recovered. If we consider that daily cycling may add years to an individual's life, then we should conclude that this discouragement of cycling constitutes a negative public health policy.

What's the Big Deal? It's Just a Sport

In general it is not the recreational or sport cyclist who is resistant to helmetization. The modern culture of high speed bike racing is very consumer-oriented, and $200 helmets are as much a status and style accessory as colourful Lycra body suits and sci-fi sunglasses. The extreme downhill MTB crowd actually like to brag about the spectacular face plants and head bonks they have survived, and given their choice of terrain and riding style, helmets seem advisable. They are more likely to experience falls than collisions with 2-ton vehicles, out in the woods and the mud.

The cyclist who is likely to resist helmetization is much like the ordinary pedestrian who sees no need to wear a full hockey goalkeeper outfit just to walk to the corner store. People who ride at moderate speeds, on even, paved surfaces -- not for thrills but for daily utility like grocery shopping and commuting to work -- are not at high risk and consider biking a simple, low-impact, normal way to get about. Just like our cyclist friends in the Netherlands, except that in the US the quotidian cyclist is a tiny minority.

The average person doesn't put on special shoes, clothes, or a special attitude to walk to the corner store, and they tend, reasonably enough, to resist having such ordinary activities redefined as abnormal and requiring specialized sporting gear. (Though watch out, the trend may be starting! Check out this humorous essay on "technical sport walking".

Bike helmets really are specialized sporting gear; they started out in the pro racing world. Racing organizations and clubs are at the mercy of lawsuits and insurance restrictions like most other organizers and promoters, and when getting large groups of cyclists together to descend mountain roads at maximum velocity, they are perhaps not foolish to require helmets. They have to keep the lawyers happy.

But the helmet manufacturers and marketers seem now to be dazzled by the prospect of unlimited sales opportunities if they enlist national and local governments to force the citizenry to buy helmets for any ordinary use of a bicycle. It's a pity that so many governments, and so many ordinary people, are buying the hard sell. The net effect is to convince people that cycling is hazardous, encourage them back into their cars, and make the streets more dangerous for the remaining riders. It really is a big deal. And it's not just a sport.

But It's Common Sense...

Many people's attitude to bike helmet use and MHLs is that "it's just common sense" that wearing a helmet has to make you safer, and therefore forcing everyone to wear helmets has to make society safer. Unfortunately, many things that are "common sense" are not true.

On the simplest level, plain common sense will tell you that the Earth is flat, not spherical. Plain common sense will tell you that objects are solid, not made up of mostly empty space with some weird invisible particles whirling around in it -- what a ridiculous notion! Plain common sense will tell you that if you have congestion on a road system, all you have to do is add more lanes. Plain common sense will not tell you how important the millions of micro-organisms are that inhabit a cubic foot of soil -- it's just dirt, for heaven's sakes. Common sense is not always a reliable guide to the real world.

Human beings get in a lot of trouble by following "common sense." It has its place, but often it's no substitute for a serious analytical, quantitative study of real events. Analytical study tells us that widening roads never relieves congestion for more than a very brief period, after which congestion actually worsens. Analytical study tells us that agriculture would never have succeeded if it weren't for those micro-organisms in the soil. Analytical study tells us that it's not wise to give hot liquids to a hypothermia victim -- the "common sense" approach can actually kill him or her.

When we do a real review of the impact of bike helmet laws in the real world, we find that neither bicycle nor motorcycle helmet enforcement has produced any statistically meaningful reduction in fatalities. The "common sense" approach has not panned out in reality. And we also find that mandatory helmetizing has discouraged cycling, and this at a time in human history when we desperately need to encourage cycling and reduce the use of automobiles. We need a little less attention to common sense; a little less wishful thinking and superstition; and a little more attention to actuarial statistics.