What about Illinois fatalities and helmets?

Illinois only had a universal helmet law for two short years; passed in 1967, it was repealed in 1969. Illinois checks seat belt and helmet usage for one week each year in June or July. Only DOT/Snell helmets are counted. Limitations of the NOPUS survey (which also measures seatbelt usage) are many—one obvious one is the weather which may lead to more or less helmet usage.

From 1998-2007, helmet usage by percentage:

98 99 00 01 02 03 04 05 06 07
Helmet 29.9% 29.1% 27.7% 22% 26.3% 35.9% 36.1% 37.6% 35.5% 29.5%
Non-Helmet 70.1% 70.9% 72.9% 78% 73.7% 64.1% 63.9% 62.1% 64.5% 70.5%

In Illinois, the median helmet usage is approximately 30% and the non-helmet usage is approximately 70%.

IL Observed Helmet UseHowever, in the five years from 2002-2006, helmet usage rose significantly (≥9.2%). In 2007, helmet use dropped 6% and was essentially what it was in 1999. If this is a one-year blip, helmet usage appears to be increasing though the reason(s) are unknown.

It raises the question: from whence comes this increase in helmet use? Is a result of new riders? Different kinds of motorcycles (as sportbike/tourers are associated with helmet usage)? Or have experienced riders decided to wear a helmet? Since training has increased so much in the past five years, does this indicate training does influence helmet usage—and there is anecdotal evidence that it does.  These questions are discussion-worthy—and research worthy.

Setting that aside and merely based on their proportion of the motorcycling population, it would not be untoward if unhelmeted fatalities were 70% and helmeted fatalities were 30%.

As we see from the table, unhelmeted riders are from 60% to a high of 78% of fatalities:

97 98 99 00 01 02 03 04 05 06 07
Fatalities 82 99 103 128 138 103 140 161 159 133 161
Helmeted 13.3% 2.3% 16.5% 11.1% 12.9% 24% 12.6% 18.5% 18.5% 20.5% 17.8%


66.3% 74.7% 70.9% 76.2% 75% 60% 76.9% 75.8% 75.8% 78% 77.1%
Unknown 20.5% 23.2% 12.6% 12.7% 12.1% 16% 10.5% 5.7% 7% 1.5% 5.1%

In all but three of those years, unhelmeted riders are over-represented for their proportion of the motorcycling population by 5-8% with a median of 75.8%—or 5.8% over their proportion of the population.

Otoh, helmeted riders, being 30% of the riding population, could be expected to contribute that percentage of fatalities—and yet they do not. Instead, they are significantly underrepresented in fatalities by 6-24% in every single year with a median of 16.5%.

Granted, the “unknown” category is large enough in almost all years to make a significant difference depending on how many of those riders were wearing helmets or not. “Unknown” means simply that—in that number of cases, the police and/or hospital report did not include the information about helmet use or non-use. And it varies quite a bit from year-to-year. This does not negate the trends in the known numbers and the percentages they comprise—so we’ll note the unknown category and set it aside.

If all else is equal, the numbers in Illinois seem to support the position that helmets save lives. But that’s the key phrase: is all else equal?

Do both groups ride as often, as far and as long in similar traffic, on similar roads at similar times? No one knows. Or do those who choose to wear helmets because of perceived safety benefit also choose other behaviors associated with safety benefits such as training or not drinking and riding, etc. All those things can make a significant difference in risk factors and affect the number of deaths.

If, however, all else is equal then the consistent under-representation for helmeted fatalities does appear to support the belief helmets save lives. Based on the median over 11 years, 13.5% fewer died than would be expected. As good as that is, it’s nowhere near NHTSA’s claim that helmets are 37% effective. NHTSA’s percentage  was based on doctor’s theorizing which riders could’ve been saved if only they had worn a helmet.

However, if riding without a helmet is as dangerous as we’ve been led to believe, the 5.8% difference between expected and actual contribution for unhelmeted fatalities barely reaches the level of significance.

Otoh, as we saw in Idaho and Pennsylvania, helmeted fatalities are increasing at a faster rate than unhelmeted fatalities:IL H Unh v Overall fatalitiesRemoving helmeted fatalities from the graph gives a very different picture of what is happening in Illinois:

IL Unhelmeted fatalities v Overall Fatalities

While unhelmeted fatalities increased, they did so proportionally in a remarkably consistent way across all the years. That’s not at all what happens if only helmeted fatalities are compared with overall fatalities:

IL Helmeted Fatalities v Overall Fatalities

We noted the pattern of increased helmet usage at the beginning of the entry. So let’s see if that explains it:

IL Observed helmet use v helmeted fatalities

There is a rough correspondence but the explanation that more helmeted riders simply increases the chances that more helmeted riders will die.

Over 11 years, Illinois’ fatalities increased by just over 94%. We already know that it’s not due to increases in motorcycle registrations—i.e., it’s not as easy as “more riders on the road, more deaths”. Pro-helmet law advocates cite deaths increasing when laws are repealed. Illinios and Idaho’s experience, however, suggest that the reverse is not true: helmet use can increase but not have a demonstrated effect on the fatality rate.

In fact, helmet usage increased over the 11 years but the greatest increase was  9.2%. In 2007, it returned to the 1997 level. However, from 1997-2007 helmeted fatalities rose 154% while unhelmeted fatalities only rose 120%. That enormous increase in helmeted fatalities cannot be simply explained by “more riders wearing helmets means it’s reasonable that more helmeted riders die”.

While helmeted riders are significantly underrepresented in fatalities, the enormous increase in helmeted fatalities should cause motorcycle safety experts concern—it deserves both discussion and study.

Training and helmets?

It’s often implied that helmet use increases because of training whether because training convinces people to wear helmets or because more safety-minded people take both training and make the helmet choice. Comparing observed helmet use with those who took and passed training we see:

IL Observed helmet use v passed training

Now let’s look at helmeted fatalities v. those who have passed the course:

IL Passed course v helmeted fatalities

Now let’s compare unhelmeted fatalities and those who passed the course:

IL Passed course v unhelmeted fatalities

I don’t have a clue what all of this means, but this I’m sure of: at the very least, the fatality picture in Illinois—and in the entire USA—is much more complicated than slapping a helmet on everyone’s head or mandating training.

While there may be more than one explanation, it does appear the correlation between trained licensed riders and helmeted fatalities does appear to be stronger than between trained and observed helmet use and trained and unhelmeted fatalities. It raises the possibility that training—as has been found in several studies—increases a rider’s likelihood to be accident-involved—and training and helmet use increases it that much more.

The easy answers are not sufficient to explain what’s happening on our roads. While some may take comfort that the fatality rate is no longer rising, that does nothing to explain why it did and why riders are really dying on our roads.

Explore posts in the same categories: History, Instructors, Motorcycle helmet use, Motorcycle Industry, Motorcycle Rights, Motorcycle Safety, Motorcycle Safety Foundation, Motorcycle Training, State Motorcycle Safety Programs

3 Comments on “What about Illinois fatalities and helmets?”

  1. gymnast Says:

    Voluntary helmet usage studies (based on empirical observations) in the late 70’s and early 80s conducted by the Safety Center, Southern Illinois University in Illinois found that the differences (variance) in rates of usage were largely accounted for by differences in weather conditions at the time the observations are made. The colder and and more inclement the weather, the greater the voluntary helmet use, conversely the hotter and more ideal the weather, the less voluntary helmet usage. The results of the study were reported at the meeting of the International Association for Automotive Medicine conference held at Louisville Kentucky in the early 80s.

    Studies by Hemmerling and Ford also conducted at SIU-C during the mid 70s to the early 80s showed a relationship between a riders head protection attitude and knowledge scale scores and the predictability of helmet usage.

  2. gymnast Says:

    Wendy, what I am implying is that if one includes temperature as a factor in the graph of helmet use VS not helmet use of fatally injured riders, one may find that more helmeted rider fatalities occur during inclement weather and that unhelmeted fatalities are more prevalent during more ideal riding conditions in elective helmet use states.

    2 cents worth

  3. wmoon Says:

    That may be. It depends on what you mean by inclement weather. The vast majority of rider fatalities occur on dry, clear days, though I do not know if anyone has done a temperature study in relation to fatalities. While I’m familiar with what those studies found back then, I wonder if that would be true today? After all, attitudes have significantly changed in terms of seat belt use and helmet use was regarded differently back then. It may well be that you’re correct. But it could be that the helmet issue has become so polarized that the vast majority of riders have taken a position and either wear or don’t wear it. What is certain is that neither of us know for sure. : )

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