Helmet laws fail maths test
...number crunching report shows compulsory helmet law would do more harm than good

The hotly contested issue of whether bicycle helmets should be made mandatory benefits from some new, mathematical, evidence today.

According to a new study, by Piet de Jong, a mathematician at Macquarie University in Sydney, Australia, the answer is no. He says bicycle helmet laws would cost the US $4.8 billion per year, Netherlands $1.9 billion, and the UK $0.4 billion.

Helmet laws like those in effect in Australia result in a substantial cost to the healthcare system because savings from fewer head injuries pale in comparison to costs incurred by decreases in cycling, according to de Jong’s mathematical model.

Scrolling through the pages of eye-bulging mathematical equations to the section at the end of the report marked, “Conclusion”, we extracted the following.

“The model recognizes one health benefit (exercise) and one health cost (injuries). A positive net benefit occurs if and only if the proportionate drop in cycling multiplied by a coefficient, called the bicycling beta, is less than the proportionate increase in accident costs when not wearing a helmet.

“The bicycling beta captures the relative benefit of exercise compared to accidents. Using widely cited estimates of the exercise benefit of cycling, costs of head injuries and reductions in cycling leads to the conclusion that bicycle helmet laws do not deliver a positive societal health benefit.”

ie. compulsory helmet laws = bad.

While we here at road.cc felt slightly under-qualified to fully interpret the complicated equations (see below) employed by the good mathematician, luckily the New Scientist has done it already.


Their conclusions of de Jong’s conclusions show that only under extreme, theoretical circumstances do mandatory helmet laws not end up costing healthcare systems.

"Even under very favourable assumptions to the pro-helmet lobby group, it's very hard to get a benefit," de Jong told the publication.

Read the full report here

Find out what the CTC has to say about the matter here


purplecup [217 posts] 6 years ago

Well it usually gets dragged out in these debates, so let's have it first up: here's the graph of helmet use vs % head injuries from New zealand showing the change in head injuries that compulsion brought about. You may notice that it's not, erm, startling...

wild man [297 posts] 6 years ago

Welcome news, although from my libertarian point of view irrelevant to arguments about legislation- it's not like cyclists are selfishly setting out to cost the NHS money by seeking the worst possible head injuries. Inform us of the risk and let us decide for ourselves.

As a baldie, I would judge that the 100% chance of looking ridiculous with helmet tan lines would affect my Darwinian prospects more than the minute chance of fatal injury.

dph [5 posts] 6 years ago

I have always believed that this is a matter of personal choice. It is my choice that I wear a helmet - I haven't always worn one. Having come off my bike on a sharp corner with loose grit / sand, my head hit one of the large stones marking the road edge (& stopping traffic from parking there). My helmet smashed, I had a few bruises, gravel rash & dented ego, but otherwise OK.

In the majority of accidents, where other vehicles are concerned, the speed at which the cyclists are hit is much more of an issue, and in those instances, a cycle helmet would be of no benefit at all.