Risk Progress

I’m writing a short paper on recent trends in risk exposure so I went to this webpage to learn some facts about motor vehicle deaths per mile of driving.  We know that crime and pollution risk have both fallen sharply in big cities over the last 20 years but did you know that fatalities per 100,000 vehicles has fallen from 21 to 13 between 1994 and 2009 and fatalities per 100 million miles of driving over the same time period fell from 1.73 to 1.14.   For similar trends in fatalities per mile of air travel see Nancy Rose’s 1992 JEP paper.  That’s progress.   I look at the life expectancy tables (see Table 1) and I see a ten year increase in USA life expectancy for someone born in 2003 relative to someone born in 1950.   While we focus on what to do with the 1%, don’t forget about the average.  The 1% can’t be enjoying all of the gains that I’ve listed above.


Author: Matthew E. Kahn

Professor of Economics at UCLA.

21 thoughts on “Risk Progress”

  1. Odds are that the decline in automobile deaths is due to more safety regulations. Enforced seat belt usage, mandatory air bags, and the like.

  2. Yes, regulated items such as seat belts, air bags, better structures (deformable front and rear clips with much stronger bodies surrounding the passengers) are a large part of the decline. I’ll add some non-mandated items such as better brakes (disc vs drum), better tires, anti-lock brakes, and stability/anti-skid systems.

    1. Antilock brakes (ABS) are a mixed blessing. They work extremely well for drivers who understand how they operate. They don’t work so well for drivers who don’t.

      These drivers fall into two groups. The first think ABS is a miracle that overcomes road conditions. They don’t. You can stop in a shorter distance on wet pavement with ABS, but not as short as on dry pavement. All of the usual safety precautions in inclement weather apply. The second group didn’t learn that ABS systems in operation sound and feel like something awful is happening under your right foot. The ABS system engages in an emergency and these drivers release pressure on the brake pedal, or worse, get off the brake entirely.

  3. What is this, let them eat airbags?

    America’s road fatalities per 100,000 is 11 in 2009. Before the recession it was 14-15. Here some countries with at least half that:

    3: Sweden, UK, Iceland, Japan
    4: Holland, Germany, Ireland, Switzerland
    5: Australia, Norway, Israel
    6: Finland, Spain, France
    7: Denmark

    America is terrible at transportation safety. Don’t let the glib economist tell you otherwise.

    1. Fatalities per 100 million miles of driven might be more telling since Americans drive a lot more miles than the drivers in most of the countries listed.

        1. I said zero about whether driving more miles was a good thing. Compared to the countries on your list, the US very large and sparsely populated country. A lot of US drivers have to drive a lot of miles to get to the places they want to get to.

          1. Well… for the (really pretty small) portion of U.S. drivers who live in the rural counties of the Plains and the west, driving long distances is necessary, although I’d bet they don’t do those long-distance trips too often (probably once a week for the shopping trip). The vast majority of Americans who have long commutes and longish drives for shopping do so because they choose to.

            But yeah, showing the stats on a per-vehicle basis combines two effects and confuses the issue of the inherent safety of the system with that of usage of the system.

            Now as far as contributors to safety go in other countries, I don’t know about the other countries on the list, but Germany has very stringent licensing laws. Before you can get a drivers license in Germany you have to demonstrate you can actually control the damned car, not just drive around the block and maybe parallel park.

            In Japan, Tokyo (at least) is densely populated enough to support a rail and subway system that puts New York to shame, and isn’t entirely downtown-focused. Google “tokyo railway map” and you’ll find this


            This map shows pretty much all of the routes around the capital area (and omits numerous stations I’m aware of for clarity). Most Tokyo families have a car, but it gets used very seldom (probably a major shopping trip on weekends and an occasional trip around holidays to visit grandma and grandpa). Having said that, average Tokyoites live at a level of density that most Americans just wouldn’t put up with.

          2. Deaths per passenger mile or per passenger hour would be even better metrics for comparisons between modes of travel and countries.

  4. The nice thing about the traffic fatality decline is that it rebuts a favorite Chicago meme: Sam Peltzman’s study that purported to prove that seat belts cost lives on net, as they supposedly encourage drivers to drive more dangerously.

    1. True that. I wouldn’t doubt there’s a partial offset from more aggressive driving as drivers feel more secure from seat belts, air bags, etc., but I’d seriously doubt that these features have made driving more dangerous on net. As an example, I’ve found many of the nice suburban housewives in SUV’s with their kids securely strapped into the back seat are some of the most aggressive drivers around, presumably because they feel well nigh invulnerable.

      1. I’ve seen plenty of those surburban wives busy on their phones as they drive — what appears to be aggressive driving may often be clueless inattentiveness.

    2. I remember that one. His story about an offset was cleverly pitched to appeal to an economist’s intuition, but as Don K says, that intuition should be that such an offset or secondary effect would be smaller than the primary effect. Insisting that the regulations would actually reduce safety on net gave the game away.

      He got the desired result in a straightforward scam: he made trend improvements in auto safety his baseline. Any regulatory intervention had to not just continue the trend reduction in injuries, but to accelerate the reduction in injuries, or it was doing the opposite.

      1. IOW, he’s a Chicago economist.

        And it’s clear by now in general that people are bad at assessing quantitative risks and small rates (see Kahneman, Tversky, etc.).

  5. Life expectancy in the USA is pretty mediocre in the OECD universe. In 2007 I checked and the ranking had not changed much over time. Infant mortality was worse then than Taiwan´s. High inequality is not good for life expectancy, so Mathew´s hint that the 99% should feel less aggrieved is unsound.

    1. True; but the U.S. is a large and diverse country. League tables ranking countries whose populations differ by one to many orders of magnitude should take that into account, but rarely do. The point I would make is that life expectancy is a really fundamental indicator of the well being of a society; not completely free of ambiguity (see overpopulation, age-group demographics), but powerful nonetheless. So long as it continues to rise, on a national, regional or planetary bases, that is reason for long-term optimism for that society even in trouble times. Which, after all, they all are.

  6. But the huge disparities between the 1% and the rest of us drags up or down the average for any given stat. I’d recommend using the median, but as an economist you need not be bothered by the real word, or mathematics as long as you conclusins are “neat and clean.” Carry on!

  7. No, it’s not going to the top 1 percent, but it’s pretty much going only to the top half:

    Remaining years of life expectancy for male Social Security–covered workers, by earnings group (top half/bottom half), age, and year of birth
    1912 1917 1922 1927 1932 1937 1941
    top 15.5 16.5 17.5 18.5 19.6 20.6 21.5
    bottom 14.8 15.0 15.3 15.5 15.7 16.0 16.1

    Source: Social Security Administration, Trends in Mortality Differentials and Life Expectancy for Male Social Security-Covered Workers, by Socioeconomic Status (http://www.ssa.gov/policy/docs/ssb/v67n3/v67n3p1.html)

  8. Didn’t a paper not too long ago look at the health disparities between quintiles or similar, and find the gains going to the rich, while the mugs and mopes received little or no gains in health measures? Surely I’m not supposed to believe trickle-on economics works with health outcomes too?!

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