The number one cause of traffic fatalities

Please don’t text while driving.

Note: I have updated this post to reflect a response I received from Matt Richtel.

A data illustration follows the rant.

I don’t yet have a copy of Matt Richtel’s new book, A Deadly Wandering: A Tale of Tragedy and Redemption in the Age of Attention. Based on his Pulitzer-prize winning reporting for the New York Times, however, I’m afraid it’s unlikely to do justice to the complexity of the relationship between mobile phones and motor vehicle accidents. Worse, I fear it distracts attention from the most important cause of traffic fatalities: driving.

A bad sign

The other day Richtel tweeted a link to this old news article that claims texting causes more fatal accidents for teens than alcohol. The article says some researcher estimates “more than 3,000 annual teen deaths from texting,” but there is no reference to a study or any source for the data used to make the estimate. As I previously noted, that’s not plausible.

In fact, only 2,823 teens teens died in motor vehicle accidents in 2012 (only 2,228 of whom were vehicle occupants). So, I get 7.7 teens per day dying in motor vehicle accidents, regardless of the cause. I’m no Pulitzer-prize winning New York Times journalist, but I reckon that makes this giant factoid on Richtel’s website wrong, which doesn’t bode well for the book:

richtelpage

In fact, I suspect the 11-per-day meme comes from Mother Jones (or someone they got it from) doing the math wrong on that Newsday number of 3,000 per year and calling it “nearly a dozen” (3,000 is 8.2 per day). And if you Google around looking for this 11-per day statistic, you find sites like textinganddrivingsafety.com, which, like Richtel does in his website video, attributes the statistic to the “Institute for Highway Safety.” I think they mean the Insurance Institute for Highway Safety, which is the source I used for the 2,823 number above. (The fact that he gets the name wrong suggests he got the statistic second-hand.) IIHS has an extensive page of facts on distracted driving, which doesn’t have any fact like this (they actually express skepticism about inflated claims of cellphone effects).

After I contacted him to complain about that 11-teens-per-day statistic, Richtel pointed out that the page I linked to is run by his publisher, not him, and that he had asked them to “deal with that stat.” I now see that the page includes a footnote that says, “Statistic taken from the Insurance Institute for Highway Safety’s Fatality Facts.” I don’t think that’s true, however, since the “Fatality Facts” page for teenagers still shows 2,228 teens (passengers and drivers) killed in 2012. Richtel added in his email to me:

As I’ve written in previous writings, the cell phone industry also takes your position that fatality rates have fallen. It’s a fair question. Many safety advocates point to air bags, anti-lock brakes and wider roads — billions spent on safety — driving down accident rates (although accidents per miles driven is more complex). These advocates say that accidents would’ve fallen far faster without mobile phones and texting. And they point out that rates have fallen far faster in other countries (deaths per 100,000 drivers) that have tougher laws. In fact, the U.S. rates, they say, have fallen less far than most other countries. Thank you for your thoughtful commentary on this. I think it’s a worthy issue for conversation.

I appreciate his response. Now I’ll read the book before complaining about him any more.

The shocking truth

I generally oppose scare-mongering manipulations of data that take advantage of common ignorance. The people selling mobile-phone panic don’t dwell on the fact that the roads are getting safer and safer, and just let you go on assuming they’re getting more and more dangerous. I reviewed all that here, showing the increase in mobile phone subscriptions relative to the decline in traffic accidents, injuries, and deaths.

That doesn’t mean texting and driving isn’t dangerous. I’m sure it is. Cell phone bans may be a good idea, although the evidence that they save lives is mixed. But the overall situation is surely more complicated than TEXTING-WHILE-DRIVING EPIDEMIC suggests. The whole story doesn’t seem right — how can phones be so dangerous, and growing more and more pervasive, while accidents and injuries fall? At the very least, a powerful part of the explanation is being left out. (I wonder if phones displace other distractions, like eating and putting on makeup; or if some people drive more cautiously while they’re using their phones, to compensate for their distraction; or if distracted phone users were simply the worst drivers already.)

Beyond the general complaint about misleading people and abusing our ignorance, however, the texting scare distracts us (I know, it’s ironic) from the giant problem staring us in the face: our addiction to private vehicles itself costs thousands of lives a year (not including the environmental effects).

To illustrate this, I went through all the trouble of getting data on mobile phone subscriptions by state, to compare with state traffic fatality rates, only to find this: nothing:

cellphones traffic deaths with NEJM.xlsx

What does predict deaths? Driving. This isn’t a joke. Sometimes the obvious answer is obvious because it’s the answer:

cellphones traffic deaths with NEJM.xlsx

If you’re interested, I also put both of these variables in a regression, along with age and sex composition of the states, and the percentage of employed people who drive to work. Only the miles and drive-to-work rates were correlated with vehicle deaths. Mobile phone subscriptions had no effect at all.

Also, pickups?

Failing to find a demographic predictor that accounts for any of the variation after that explained by miles driven, I tried one more thing. I calculated each state’s deviation from the line predicted by miles driven (for example Alaska, where they only drive 6.3 thousand miles per person, is predicted to have 4.5 deaths per 100,000 but they actually have 8.1, putting that state 3.6 points above the line). Taking those numbers and pouring them into the Google correlate tool, I asked what people in those states with higher-than-expected death rates are searching for. And the leading answer is large, American pickup trucks. Among the 100 searches most correlated with this variable, 10 were about Chevy, Dodge, or Ford pickup trucks, like “2008 chevy colorado” (r = .68), shown here:

deaths-searches

I could think of several reasons why places where people are into pickup trucks have more than their predicted share of fatal accidents.

So, to sum up: texting while driving is dangerous and getting more common as driving is getting safer, but driving still kills thousands of Americans every year, making it the umbrella social problem under which texting may be one contributing factor.

I used this analogy before, and the parallel isn’t perfect, but the texting panic reminds me of the 1970s “Crying Indian” ad I used to see when I was watching Saturday morning cartoons. The ad famously pivoted from industrial pollution to littering in the climactic final seconds:

Conclusion: Keep your eye on the ball.

17 Comments

Filed under In the news

17 responses to “The number one cause of traffic fatalities

  1. Kira

    This article offers a very important insight, especially to the people my age. It’s very hard to find a 17 year old who isn’t on their phone at almost all times, and this includes while driving. The shocking statistic (11 teenagers per day) gives us a reality check that texting while driving is, in fact, very dangerous. Most people, including myself, are guilty of it, but there needs to be some sort of wide-spread prevention tactic. Be it designing cars that disable texting while the car is in motion or some other action, something drastic needs to change. When I was little, children weren’t getting phones until middle or high school, but now I see children in the early stages of elementary school walking around with iPhones. This just shows the texting while driving problem will only increase in the future.
    I also liked the commentary about our driving society. It’s pure laziness that Americans will drive to a place three blocks away as opposed to just walking. According to this article, there is concrete proof that driving more increases the chances of dying in a vehicular accident.
    Both of these points show that we desperately need a change in our culture/society in order to start saving the lives of those dying in vehicular accidents.

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  2. Andy

    This post is one of your best yet. The motor vehicle accident death rate per mile driven in the US is pretty similar to the western european aveage. The reason why our per capita rate is so much higher is that we just drive a ton more. But it’s tough for people to see.

    This makes me think of the American Society of Criminology’s position against using crime statistics to compare crime across places, because it ignores the factors that increase crime in ALL places. Same with driving. If everyone’ driving, our attention will only be on the ways we differ, like texting. Well done.

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  3. Your logic here is terrible. First of all, that first graph is SO scattered, that no scientist or mathematician in his right mind would deign use it to create a trend line. Any peer review would rip that apart immediately. Having a subscription to a mobile phone also does not mean the person is *using* the phone while driving. Why not make it a graph with more points where the x-axis is “Number of people who text while driving.” Also, the graph clearly states that in some cases there are over 105 mobile phone subscribers per 100 population. This is non sequitur. Second, the following graph is pointless. DRIVING does not cause ANY deaths. It is accidents caused while driving that cause deaths. The longer you are in your car, the greater the chance of you having an accident in it. I guarantee you you could make another graph where on the y-axis you put “deaths in home per 100k population” and on the x-axis “hours spent in the home” and get the EXACT SAME RESULT.
    Now, perhaps the rate of teen deaths related to texting has been exaggerated, but to say that driving is what causes driving deaths is a logical fallacy. Instead, do your homework and find out what is the number 1 cause of *vehicle accidents.* Heck, impress us and break it down to age, sex, race, income, and political affiliation.

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    • vijay

      Yes; If i had made the above comment, Philip would never have published it. The second graph is not even graph; it is just a graphical representation of the data in
      http://www.iihs.org/iihs/topics/t/general-statistics/fatalityfacts/state-by-state-overview by state.

      What does that figure even mean? If you live in DC, you are living in a 20X20 grid, and the distances traveled are negligible. In the southern and western states, where the distances are large, and public transport is not available, you are forced to drive long distances and chances of fatality are higher. None of this is relevant to texting and driving, which is harmful independent of the distance, but cannot be quantified because there is no category of deaths classified as dead due to texting and driving.

      In any case, software to read out texts and transcribe the spoken word as text, is readily available. If the user can make use of the software, then texting and crashing will be come irrelevant. But none of the statistics quoted above is relevant to the issue under consideration, because, data for what caused the crash is not readily available in most traffic fatalities.

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  4. Pingback: Why you can’t understand the texting and driving problem in one chart, in one chart | Family Inequality

  5. Oy. *Perhaps* there isn’t a deadly texting while epidemic– but this does not even come close to proving that. The first graph implies that traffic fatalities are down while cell phone subscriptions are up. However, traffic fatalies are down since 1983 for a large number of reasons–increased seat belt use, airbags, safer cars, safer roads, and decreases in drunk driving. There might be an uptick in deaths due to text hidden among all those other variables, there might not be, but without controlling for those significant variables you will of course, find nothing.

    Liked by 1 person

  6. SC

    What about non-fatal accidents? Ultimately that’s a more significant economic problem, and depending on non-fatal casualties, potentially a greater public health problem.

    As noted, the advances in traffic and vehicle safety features, as well as medical care, could be holding the fatality rate low even in the face of more injurious accidents (I don’t know). I wonder if this is not dissimilar to the relatively low fatality rate in our recent wars, but the much higher non-fatal casualty rate due to better equipment and medical care. In that case, it’s not that war is “safer” but that we are better at preventing death at war, could something similar be happening here, where there are more dangerous accidents, but we are better at keeping their victims alive, if still harmed?

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    • No, non-injury crashes are down too.

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      • SC

        Two things:
        First, my point was that fatal crashes may have declined, but that non-fatal injury-crashed risen due to medical and vehicle safety advances. Data on non-injury crashes is irrelevant to this argument, though I would love to see some data supporting the claim that non-injury crashes are down.

        Second:
        This study suggests that non-fatal injuries have risen in the past few years:
        http://www-nrd.nhtsa.dot.gov/Pubs/811856.pdf
        after declining steadily from 1996 to 2009. The same study also shows (though only over two years, so I’d have to find a longer series of data) that non-occupant injuries and fatalities are rising, which could support my belief that technology has made occupants safer, but obviously non-occupants do not benefit from those advances, and would suffer if overall accident rates are higher. Along these lines, there has been a sharp increase in motorcycle fatalities between 2003 and 2012, that’s another population that would not benefit from improved car safety measures, and would suffer if drivers are broadly speaking more dangerous due to distraction.

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  7. Crystal

    I wonder how much the elevated risk of death in places like Montana and Alaska has to do with snow, ice, and large mammals? Maybe they’re just more likely to slip on ice or hit a deer or moose crossing the road. (No snow or ice where I live but you do have to watch for deer, even in the ‘burbs!)

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  8. Pingback: Absence of correlation does not imply absence of causation | Common Infirmities

  9. I had this observation (if texting is so dangerous, why aren’t traffic fatalities up?) myself a while ago. It’s really perplexing and the amount of cognitive dissonance in the comments section aruging against the conclusion is revealing.

    Anyway, I think the issue might be with our paradigm of “distracted” driving entirely. A lot of the data on the effects of cell phones/texting/alcohol in crashes was done in driving simulators, which don’t really simulate actual road conditions in a way that satisfies me. From what they discovered about alcohol, it seemed like the conclusion was “alcohol causes crashes by lowering attention and decreasing reaction time.” Maybe this misses the point.

    I’d hypothesize that very few serious accidents are caused by loss of attention at all. The problem with drunk driving might be that 1) you might literally pass out behind the wheel 2) a person much more likely to drive unusually fast and aggressive when drunk. I’m basing this mostly on anecdotal/inferential data, but that would explain why so many drunk driving accidents happen in rural, low-traffic areas, rather than in the types of busy, at-grade intersections most traffic accidents occur in. The effect of “inattention,” which is what the driving simulators measure, may be relatively small, which is why texting produces so little danger despite causing similar amounts of inattention to drunkenness in simulators. Just a thought.

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  10. Pingback: Research on teen crashes confirms that reporters selling books on phone risks hype phone risks | Family Inequality

  11. Pingback: NYT’s Richtel traffic hype soars at historic rate | Family Inequality

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