Study: Helmet laws discourage bicycling

Putting on the helmet

The Freakonomics blog is covering a research that seems to confirm what many bicycle advocates have been saying for years: Laws requiring helmets while bicycling reduce the amount of bicycling.

The study, entitled "Intended and Unintended Effects of Youth Bicycle Helmet Laws" (PDF), looked at children 15 years of age and under--the age group most commonly the subject of bicycle helmet requirements in the U.S.

The research showed that the amount of bicycling is reduced 4-5% while the use of helmets is increased by 29-35% measured one way or 10-23% measured a different way.  The number of bicycle fatalities is reduced by 19%.

Of course those raw percentages don't tell the full story, because the "whole" to which the percentage relates is quite different in each case.  

For instance, in Missouri our best estimate is that about 7-800,000 children bicycle regularly.  About 200,000 of those wear a helmet regularly. On average there are about 8 Missouri bicycle fatalities per year, and about 20% of those are children.

Putting those numbers together with the percentages from the study means:

• A reduction of 5% of children bicycling means that 35,000 to 40,000 fewer children are bicycling.  
  
  
• An increase of 29-35% in helmet use is not as significant as it might appear.  One study found only 24 of 359 students bicycling to school wore a helmet; an estimate of overall helmet use by bicyclists is about 25%.  Assuming that rate for Missouri children, a state law requiring bicycle helmets would encourage about 60,000 more children to wear helmets while discouraging 35-40,000 from bicycling altogether. 
  
  
• A reduction in fatalities of 19% would mean about 8 child bicycle fatalities in six years rather than the current 10.

Eliminating two child fatalities seems like a worthwhile accomplishment, but:

• Part of the reduction in fatalities is simply because there was a reduction in the amount of bicycling--if the amount of bicycling goes down 5% it wouldn't be surprising if the amount of fatalities went down 5% also.
  
  
• 35-40,000 fewer children bicycling in Missouri also has a serious impact.  We are already facing high childhood obesity rates that are having a serious impact on both quality of life and life expectancy. We want to encourage more good, safe, healthy, outdoor experiences for children, not eliminate them.
  
  
• Some of the perceived reduction in fatalities is undoubtedly transferred to other activities.  Children stop bicycling because the helmet is required but shift to skateboarding, roller blading, scootering, and so on.  The main cause of fatalities in children who bicycle (riding unexpectedly out into the street and being hit by an automobile) also happen with just about the same frequency and for the same reasons with these activities.  So there may not be a reduction in fatalities so much as a shift to a different category in the accounting of them.
  
  
• Children who can't transport themselves to destinations by bicycle will rely more on automobile trips.  But more automobile trips also carry a risk of injury and fatality not that different from--perhaps even higher than--the risk of bicycling.  And automobile trips have other negatives, including congestion, pollution, cost, time for the chauffeur, and loss of independence for the child.

The Freakonomics authors add two more possible reasons: Cost of the helmets and the fact that helmets are required by law for bicycling--but not other similar activities--makes people believe that bicycling is more dangerous and discourages people from doing it.

Given all that, are laws requiring children to wear helmets while bicycling the best approach to improving overall child safety and health?  Are there other approaches that might be more effective?

What do you think? Leave your thoughts in the comments section.

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