I don't know what the evidence is for the helmet hair thing but pretty much every woman I can think of cites it. ... It's a shame, because I enjoy riding. But not more than I enjoy looking professional in a professional environment.
I can't say I have personally met many who see it as a big issue, but I can see for some it might be and it is a crime if this stops someone from bicycling. It is a fact that it is better to bicycle unhelmeted than to not bicycle at all, so if the law stops anybody the country has lost.
It is certainly noticeable in Europe that many ladies ride in their finery - I've personally seen "middle aged" ladies in dress clothes looking like they're headed to the opera. It works for men as well, I can remember the great picture I witnessed outside Utrecht (Netherlands) when a group of suit wearing, briefcase carrying, gentlemen emerged out of the morning fog riding bicycles to work in the city. The "cycle chic" movement has reached NZ and I've noticed helmets are less common among its participants.
Many years ago an elderly lady contacted me for help with a helmet exemption. She looked after her less able husband, lived in a semi-rural area, only had a bicycle for transport, and suffered headaches from the helmet. Her doctor had filled in an exemption application with her, this had been returned due to some error on the form. She returned to her doctor only to find he had left and been replaced, the new doctor refused to fill the form in correctly arguing it was better she did not ride and to ride without a helmet - the helmet law campaign had done its worse. The lady was at her wits end, concerned she wouldn't be able to care for her husband much longer if she had no transport to get to the shops etc.
I tried to engage the doctor, tried the local MP, the Minister - all to no avail. All I could do was advise she ignore the law, something she was not keen on doing.
I don't know what happened in the long run, but if she stopped bicycling not only did it likely impact her ability to care for her husband, she probably also died sooner.
All for a law which has failed to reduce injury rates and instead produced a cost to society. A tragedy.
I've come rather late to this discussion, much has been stated, quite a few questions asked, and some misconceptions aired. I'll comment on a few of the points, maybe have a bit of fun, etc...
so I'll start with a disclaimer: I am a scientist, I have researched this topic, etc. and I will endeavor to be clear about what is fact and what is opinion, but I may fail, and having researched this doesn't make my opinions right per se!
Somebody asked about seat belts, do they work?
Yes and no!
There is this little problem in safety/risk management, its called risk compensation - everybody, so some extent or other, compensates for risk, if people feel safer they take greater risks. Makes improving safety a challenge! The ideal safety measure should provide more safety than it appears, so after the increased risk taking that will result there is still some benefit. The obvious corollary is you should never oversell the benefit of a safety measure, you're just asking for it.
So back to seatbelts, do they work?
Well the observed behaviour post compulsion in the UK was that while accidents increased (risk compensation) the number of injuries to car occupants decreased. Sound like a win?
Well no it wasn't. You see when a car crashes it sometimes hits a pedestrian or a bicyclist, and more cars crashing... yes, sadly the number of pedestrians and bicyclists injured went up. Worse the increase in injuries to pedestrians and bicyclists was greater than the decrease to car occupants. Sound like a loss?
So do seatbelts work? Across the population it is debatable, but I wouldn't advise you not to wear one - just watch out for those outside your vehicle!
Now that wasn't really a diversion, as understanding the above helps understand why helmet legislation has been such a failure:
* Everybody always knew bicycling wasn't very dangerous, so how to persuade them they need a helmet? Talk up the danger! Geez, the traffic these days! No room for bicyclists... Etc. Fact: The LTSA in a public meeting in Christchurch admitted they had shot themselves in the foot over the helmet law campaign - policy was by then to encourage bicycling but they'd spent years discouraging it by talking up the danger to promote helmets...
* Now everybody thinks bicycling is hyper-dangerous and you're stupid not to protect yourself. Fact: remember "barehead, knucklehead"?
* But you've got a solution! The helmet... But in getting here you've way oversold the danger, and now are way overselling the protection provided by the "solution", which is not good... Fact: bicycle helmets are not designed, and cannot be - the laws of physics get in the way, for impacts with moving vehicles.
* Law fails... Fact: the NZ law, at best, has not produced any significant reduction in injury rates.
I noted some comments regarding "helmet hair", people being wimps for stopping riding because of the need for a helmet, etc.
While a few people might be concerned over helmet hair, I've never seen any indication it is a significant concern. But I suggest there is a bigger issue which discourages bicycling stemming from the law.
Remember to promote helmets in the first place a multi-year campaign was run to explain how dangerous bicycling is and how vital a helmet was - sure it was all hokey, but people believed...
Now put yourself in the shoes of a parent, in these days of "helicopter parents", faced with the choice of whether to let little Johnny/Jane use a highly dangerous method to get to school, so dangerous you need a helmet, or instead to use the super-safe method of driving them...
Now the parent doesn't know there are more car occupant head injuries every year than bicyclist ones (the rate per hour is similar), or that exercise and independent mobility provided by walking/bicycling is vital to their child's physical and mental development (fact: research has shown that kids who are driven to school do less well academically than those who are not, I kid you not), all they see is danger helmet required
So maybe bicycling hasn't dropped because people are wimps, or overly hair-conscious, but as a simple reaction to the misdirection that it is hyper-dangerous.
Helmets and car occupants, I know somebody brought that up.
Yes, both our and the Oz governments claim we'd save a lot more if car occupants wore helmets if the theory they used to justify the bicycle helmets laws is valid.
They claim it is.
They choose not to wear helmets on their own heads while in cars.
So their practice shows they don't believe what they claim...
Shock! The law is a political one and nothing to do with health and safety, who would have guessed???
I've written enough, so let's close with something scary but true: The Norwegians recently decided not to pursue a bicycle helmet law because their research showed the NZ & AU laws produced a 14% increase in risk.
Keep bicycling folks!
And if you wear a helmet, always ride as though you don't.