Do Bike-Helmet Laws Discourage Bicycling?

In a new working paper called “The Intended and Unintended Effects of Youth Bicycle Helmet Laws” (abstract here; pdf here), Christopher S. Carpenter and Mark Stehr offer a surprising conclusion: while mandatory helmet laws have led to increased helmet use, and while helmet use has been shown to reduce bicycle fatalities, such laws also seem to lead to a decrease in actual bike riding.


Carpenter and Stehr lay out their case compellingly. They exploit a convenient variable: the fact that helmet laws exist in only 21 states, pictured here:


While conceding that these are primarily “coastal” states, the authors note that they cover more than 50 percent of the U.S. youth population.

Their research first confirms earlier research that “helmet laws significantly reduced bicycling fatalities among youths age 0-15 (i.e., youths who were directly treated by most states’ age-16 helmet laws) by about 19 percent.”

Their research further suggests “that helmet laws significantly increased youth helmet use by 29-35 percent.”

But: “There is also robust evidence for an unintended and previously undocumented mechanism: helmet laws produced modest but statistically significant reductions in youth bicycling participation of 4-5 percent.”

The authors offer three explanations for why this may be true:

1. The cost of helmets, both monetary and social — i.e., Helmets are uncool, so if I’ve got to wear a helmet to ride my bike, I’ll find something else to do.

2. “There is evidence that youths have suboptimally high discount rates (Gruber 2001), such that some youths might place too little weight on the expected gain in future utility from the prevention of injury or death relative to the costs of wearing helmets today.”

3. Bike-helmet laws lower the price of activities similar to biking — skateboarding, rollerblading, etc. — that do not require a helmet.

These seem perfectly sensible to me, but I might add a couple other possible explanations:

1. Helmets are a hassle.

2. Helmet laws make cycling seem more dangerous than we used to think it was. Therefore, a certain kind of parent develops a bias against it, and no longer encourages his or her kids to ride a bike — or, perhaps, never even bothers to buy the kid a bike.

Whatever the case, a downturn in bike ridership may strike some people as a grievous strike against the American character. On the other hand, it’s great news for the likes of Nintendo, Sony, and Microsoft.


If you're stupid enough to ride without a helmet, Darwin's law should come into effect. The way I look at it, is that people who don't wear them are trying to upgrade the species by getting themselves killed.


Helmets are so much more accepted thanks to pro freestyle athletes. In freestyle, kids are more likely to wear helmets and pads because they know crashing is part of the process.

I broke a helmet in a wicked crash eight years ago, and only got a sore neck and scratched forehead. Since then helmets are like seat belts to me, it's uncomfortable to go without.

And to the over-protective parents who think bikes are too dangerous: Let your kids fall down and get hurt sometimes. It's part of a healthy childhood.


The nerd factor really...I had to wear a helmet before they were mandatory, so while I have survived to be a nerdy was the result of being a nerdy child.

I hated wearing a helmet so I switched to rollerblading everywhere. Not cost, just no need to wear the safety equipment.


Or because the states surveyed are coastal, the kids there are more wired than the kids in the middle of the country, and would be playing on their Wii, PlayStation and Xbox without the law. I know here in CA, fewer kids ride their bikes to school than did when I was a kid (2 generations ago) and also less than when my kids were young (1 generation ago)


The Kid in the picture is Safer on a Bike with the Helmet.
But CATNIP to a Bully !

I would never EVER wear that.


In addition, with fewer cyclists, cycling is more dangerous (people are less likely to expect cyclists to be there).

That's sometimes cited as the reason there is so little improvement in safety with mandatory helmet laws.


The potential problems I see with this analysis:

* Bike helmet enforcement is near zero
* Knowledge of bike-helmet laws is limited
* Bicycle helmets do not prevent collisions.

I suspect these are just as big a factor in mode choice as the cost of bicycle helmets.

Rob Rippengale

I rode a bike with great enjoyment in Victoria BC, before the helmet law came into effect some years ago, and especially enjoyed the feeling of the wind in my hair. As the helmet law approached, I often noticed cars in my lane giving me much more clearance than they did the bicyclist in front of me who wore a helmet. Although wearing a helmet during an accident may prevent certain injuries, I wonder if wearing a helmet actually increases the chance of a serious accident.

I would also add a reason many people don't ride bikes specifically because of the helmet law - helmet hair.

ps, I have not been on a bike since the helmet law began.


The coastal states highlighted are more urban, and city kids are less likely to bike for myriad reasons (convenience, safety, etc.).


A terrible photo to accompany the article, because the kid's helmet is not properly adjusted to actually increase safety! With the chinstrap that loose, it would go flying off in any collision. Perhaps fittingly, though, it looks "cooler" loose and dangerous than snug and safe.


Many of those states are more densely populated than the non-coastal states. The bulk of the population might live in big cities in those more densely populated states

If I lived in a big city...

* I probably wouldn't let my kid ride his bike around since there are more cars on the road.
* I would be more worried about someone stealing my kids bike
* I might be more likely to live in an apartment without a place to put a bike.


I must be missing something. The "Discussion and Conclusion" of the study asks "Why do helmet laws lead to reduced cycling?" What precedes the Conclusion, however, only presents an association between helmet laws and bicycle usage, and not a causation. As the article suggests, there might well be other factors that actually cause a decrease in bicycling, such as increased attraction of electronic games; ever-increasing motorized traffic leading to the (warranted or unwarranted) perception that bicycling is unsafe; deteriorating road surfaces caused by decreasing funds available to improve them; and so on.

The only way to determine a *causal* relation between helmets and bicycle usage is to actually query the parents/users themselves and find out *why* they ride less frequently or not at all. Note that the survey doesn't do this. It follows the question posed at the beginning of the Conclusion with several "possibilities" -- none of which the authors bothered to confirm with their sample.

But maybe I'm biased. One of my sons is alive today because he crashed wearing a bike helmet. Or so that's what his pediatrician says....



While I have been a cyclist for many years and been wearing a helmet from the time they were less than comfortable (remember the old Bell helmets), the photo shows a child who is not wearing a helmet properly with the strap dangling below his chin. What is the result of a child or adult wearing a helmet improperly in the event of an accident? Also, what is the rationale of many parents who ensure that their children wear a helmet but when riding with them go without? We should be advocating for more helmet usage and cycling in general as I have with my own children.


You say the downturn is bike ridership is great news for sellers of electronic games. One might go further and suggest that the games themselves are in competition with biking and all sorts of outdoor physical, leisure activities; they're not just a beneficiary of the downturn, but a cause as well.


Leaving aside the human/emotional arguments. What is conspicuously left out of consideration is cost of healthcare for those who are injured or killed - how many like accidents result in a rider pronounced at scene and taken straight to morgue? Since we all pay for that care, the more serious the accidents, the higher the insurance rates. Therefore, the "greivous strike against American spirit" is idiotic. Since the capitalist system means we all pay for others stupidity, choosing not to wear a helmet isn't "going rogue" it's more of what Amreica has become: getting responsible poeple to pay for your irresponsibility using the false argument that you are expressing your freedom. If you refuse to wear a helmet and agree to finance your care or allow yourself to go untreated, that would be a valid argument. As for uncool, take a look around. Very few people don't wear helmets and professional bikers do all the time. As for diggiti (#5) teach your kid to headbutt any bullies with the helmet on. A win-win for all.



Okay, here's another subject of research. Are Wii's, Nintendo's, Ipods. Guitar Hero etc decreasing kids wants for a bicycle?

Even in the absense of laws, how sure are you that the numbers of people are going to just magically fly sky high in its absense?

Look, the research is not conclusive. You can't just pinpoint at helmet laws and say that it is the only factor causing bicycling to reduce. Parents have a legit case for stopping their kids from cycling if they feel doing so in the neighborhood is asking for a deathwish. Make cycling safer and we'll see the benefits. Complain about cycling laws and do all the research you want, cycling is not going to increase on unsafe roads. Its more practical to wear the lid.


"2. Helmet laws make cycling seem more dangerous than we used to think it was. Therefore, a certain kind of parent develops a bias against it, and no longer encourages his or her kids to ride a bike - or, perhaps, never even bothers to buy the kid a bike."

I agree with this statement. I know people that think I am crazy to bike in the city, while they drive their cars.
I usually try to wear a helmet, at least when riding on the road with cars, but I don't think of cycling as unsafe, so I don't worry about it if I don't have a helmet with me.
People who think helmets are so important that they would never ride without one probably think bikes are too dangerous to ride at all.


It's none of the government's bleeping business whether I or my children wear bike helmets! I do (usually), and I wear one skiing too, but I say Down with the Nanny State!


Requiring a helmet indicates that cycling is a dangerous activity. Overly protective parents and tentative adults later fall for this, creating this false idea that helmets are necessary for riding a bicycle. There was a time when bicycles used to be considered a safe and fun mode of transportation. What happened? Oh yeah, we added more cars, traffic, suburbs, and the x-games.

Don't confuse me with being a car hater, I advocate using the right tool for the job. I'm just wondering if we'd be so concerned about helmets if people didn't FEAR riding in an urban area (coastal coincidence?). Though I have a feeling that a car's wheel would still squish my head if I fell beneath it.


Its worth noting that in countries with extremely high cycling rates, such as the Netherlands (where 25% of all trips by those over the age of 65 are made by bicycle) and Germany, helmet use is almost unheard of. Yet these countries have much lower injury and death rates than the U.S. where helmets are common.

There is little evidence that helmets are beneficial to safety.