caution tapeSo how far are we willing to go to keep ourselves safe? We’ve heard a lot of stories – we’ve experienced them! Think about all the contortions we go through at the airport – the TSA striptease comes to mind – not to mention the whole deal with having to leave water bottles and regular-sized shampoos behind for those unwilling to pay the fee for actually checking luggage. Banning guns and knives from aircraft seems like a good idea – breaking the nail file off of my nail clippers (which happened to me in Panama once) seems a bit extreme.  Drivers’ licenses and speed limits help to keep us safe from our own recklessness as well as from the mistakes of others , and drug laws are aimed at keeping us safe from our own impulses as well. Society goes to great lengths to try to keep its citizens safe – trying to stave off premature death and injury by imposing (hopefully) reasonable restrictions on what we can and cannot do. To that, we can add what we do ourselves – watching our diets, exercising, trying to live in safe parts of town, managing stress levels, and so forth. Whether societally or individually we go to great lengths to try to keep ourselves safe, and everything we do to increase our safety and security imposes limits and restricts our options.

But with all that we do, perfect safety is an oxymoron, sad to say. Or, in the words of my master’s advisor, “The most dangerous thing that happens to all of us is being born – it has a 100% fatality rate.” So, as with any search for perfection, a quest for perfect safety is doomed to failure because something will get each of us at some point. The idea, then, should be to try to push back that point as far as possible while remaining in the best health possible until then. And, I guess, to try to balance our quest to extend our lives against our desire to have a life that’s worth extending – wrapping up in bubble wrap and locking the doors might reduce risks, but it also reduces the opportunities to enjoy, appreciate, and experience life.

It’s hard to develop cirrhosis of the liver, for example, if you never drink – but then you miss out on the experience of savoring a fine wine, of sharing a beer with buddies after work (or during a big game), or the relaxation (and light buzz!) from a snifter of good cognac or a sip of single-malt scotch. For us to try to minimize the risk of liver impairment we’d have to give up the possibility of these good experiences – only you can decide for yourself if it’s worth it to add, say, a few years of life at the expense of several decades of (responsibly, of course) enjoying the occasional drink. And similarly, we can reduce traffic mortality by slowing down – at 5 miles per hour the risk of a fatal traffic accident is vanishingly low – but we sacrifice whatever we might have done in those extra hours spent on the road.

OK – so what we eat and drink, how safely we drive, and so forth are individual decisions that have scant impact on anyone else (except maybe some frustrated passengers and fellow drivers). But what about risk reduction on a societal level? For example, a recent report notes that the US is backing away from its goal of scanning 100% of all cargo containers entering the nation. Acknowledging that uninspected cargo containers are a good way to smuggle in people or weapons, Customs and Border Protection (CBP) also acknowledges that there are simply too many containers entering the country for them to have a reasonable way to scan them all. Or, rather, than a 100% scan rate is possible, but only if we hire a LOT of inspectors, develop and deploy expensive (and not 100% reliable) technology, or impose unacceptable delays on commerce. It could be that the financial and societal cost of 100% security in this area is unacceptable – we can do our best within limits, but there are limits.

What it comes down to – individually and collectively – is trying to strike a balance between quality and quantity. For example, if my doctor told me that cutting beer and potato chips entirely out of my life would add 10 years to my life I’d probably give up both. On the other hand, if he told me that it would make a difference of only a year I’d probably choose to enjoy these treats and however many years I have left. My guess is that we all have some sort of way to determine where our own balance point lies, whether we’re talking about diet, exercise, safe driving practices, going to the doctor, or whatever. Having said that, I’m also sure that our balancing act probably isn’t grounded in accurate facts so much as our gut feel and personal preferences – and unfortunately these don’t always lead us to an optimum solution. What would be nice would be if we – individually and collectively – took the time to try to understand which of the multitude of risks we face are really significant and which of the protective actions we consider taking are really effective; and hopefully to avoid worrying about risks that are minuscule and to avoid taking protective actions that, however good they might make us feel, are ineffective.


On another topic, I recently posted a piece about a graph that seemed to show the Iranians were using computer models to simulate a nuclear weapon – I mentioned that the graph was way off and that it suggested the plot might be an attempt to spread disinformation about an Iranian nuclear weapons program. It turns out that the curve itself is likely accurate, even if the axes are mis-labeled. In short, the plot may well represent Iranian progress towards developing nuclear weapons, and I may have been premature to dismiss them.


Finally – I apologize for missing last week’s posting. I just started a new job and the transition kept me a bit busy.

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2 Responses to “Safety”

  1. Len Finegold February 6, 2013 at 6:32 PM #

    I look forwards to your writing, print it out to read on train.

    And similarly, we can reduce traffic mortality by slowing down – at 5 miles per hour the risk of a fatal traffic accident is vanishingly low – but we sacrifice whatever we might have done in those extra hours spent on the road.

    I get reports from Insurance Institute for Highway Safety, and quizzed them about this once. I did rough estimates of cost/benefit of driving at various speeds. Alas, IIHS had not studied it.

    Perhaps you would?


    • Dr. Y February 6, 2013 at 7:27 PM #

      An interesting question – I don’t have a direct answer either, but there are still some ways to perhaps shed some light. To start with, I was in Saigon several years ago and was told that there are very few traffic fatalities in spite of traffic that seemed – to be charitable – anarchic. But while I was there I noticed that traffic very seldom moved much faster than 20 or so mph and I realized that it’s hard to have a fatal accident at low speeds. This makes a sort of intuitive sense – here are some numbers to back up the intuition.

      First there’s reaction time. Let’s assume for the sake of argument that it takes a half second from the time you realize there’s a problem until the time you get your foot on the brake pedal. At 60 mph your car will travel 44 feet in that half second, and you haven’t even started slowing down yet. At 30 you travel half as far, giving you twice as much time to react – possibly saving your life as well as that of the other person. Slower speeds gives more time to react.

      The other calculable factor is kinetic energy – the amount of kinetic varies as the square of the speed. So a collision at 60 mph has 4 times the kinetic energy as one at 30 mph and 9 times the kinetic energy of a 20-mph collision. Putting both of these together, slower speeds give us more time to avoid a collision and less damage in the collisions we can’t avoid.

      I have seen statistics that the highway death toll dropped significantly after the mandatory reduction in speed to 55 mph in the 1970s. On the other hand, a LOT of automobile and highway safety measures were enacted around the same time and driving safer cars on safer roads would have lowered the number of highway fatalities regardless. I’m not really sure how to disentangle these two factors – it seems reasonable to assume that some of the lives saved were the result of slower traffic, but almost certainly not all of them.

      One other thing to keep in mind is that there are tradeoffs in everything – we might be incredibly safe from traffic accidents at 5 mph, but that speed imposes a lot of constraints on how far we can travel in a given amount of time. Not to mention having to include food and pit stops in our travel plans for even relatively short trips!

      I’ll see if I can find anything less speculative and if so I’ll post it here. And thanks for your kind words!

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