Smeed’s Law and motorcycle fatalities
We’ve looked at the various pieces of the motorcycle safety puzzle and found that they all—without exception—have failed to bring the death toll down but as more riders practice them the death and injury toll goes up.
It’s time, then to explore other things that might affect the crash rate of motorcycles in America. Some of these readers have referred to—and we’ll look at them more closely. Some of them may seem quite far-fetched and some might be rather offensive. Yet, since the usual answers haven’t solved the puzzle, it’s appropriate to explore other factors—no matter how unpalatable—in case they may in part or in concert led to safer roads for riders.
We start with R.J. Smeed’s “Law” which was first published in 1949. It states that as the number of automobiles in a country increase so do fatalities in a predictable way: the number of deaths equals .0003 times the two-thirds power of the number of people times the one-third power of the number of cars.[i] After that point, road fatalities begin to fall off and then level off at a much lower point.
Despite safer cars, Smeed’s Law is still basically true in all developing countries. For example, it held true in the USA until about 1966—and his formula for the decline of traffic fatalities is very close to what has actually happened.
His friend, the eminent physicist Freeman John Dyson, wrote, “It is remarkable that the number of deaths does not depend strongly on the size of the country, the quality of the roads, the rules and regulations governing traffic, or the safety equipment installed in cars. Smeed interpreted his law as a law of human nature. The number of deaths is determined mainly by psychological factors that are independent of material circumstances. People will drive recklessly until the number of deaths reaches the maximum they can tolerate. When the number exceeds that limit, they drive more carefully. Smeed’s Law merely defines the number of deaths that we find psychologically tolerable.”[ii]
Of course, in 1965, Ralph Nader’s book, Unsafe At Any Speed, was published which both captured the general public’s growing frustration with traffic fatalities and exacerbated that frustration. From the mid-Sixties on there was a massive push for safer design, safer roads and safer crashing. Iow, Smeed was right about the linkage but assumed it would take more cars and deaths to get to the point we could no longer psychologically tolerate the death toll.
It’s true that motorcycles can’t be made as objectively safe (crush zones, front and side air bags, etc.) as cars—but then that’s true for bicyclists and pedestrians as well and their death rates have dropped in the past ten years while motorcyclist fatalities rose—and rose and rose outpacing registrations.
When it comes to automobiles and perhaps bicycles[iii], there’s not just a correlation but some kind of subconscious process at work that first allows the death toll to rise and then, eventually, lowers it.
But the key here is that drivers keep driving—they just drive safer.
The question is: does Smeed’s Law work for motorcycle registrations and rider deaths? I’ll leave it to anyone who’s better at math than I to do the math but I do wonder: How can we as riders still “psychologically tolerate” the soaring death toll?
But here’s this—even if it does, it’s a little different when it comes to motorcycles: The past 11 years is not the first surge in motorcycle registrations and fatalities in the USA. The most recent registration surge ended in the early 1980s and fatalities topped out in 1981. The death toll began dropping and bottomed out in 1997—even though registrations had begun to increase a few years earlier.
While 29 states either dropped or adjusted universal helmet laws during the 1970s while fatalities were rising, the laws weren’t reinstated yet fatalities dropped. From 1973-2001, 1.6 million were trained and all states began to require motorcycle licensing—and most were trained as fatalities were falling.
But the death toll did drop beginning in 1982—and so did registrations and then registrations started to go up in the early 1990s—and fatalities followed suit in 1998.
However since 2002, the Motorcycle Safety Foundation claims over 2 million have been trained—and yet fatalities have exceeded the height of the late 1970s-1981 surge in rider deaths.
Today, EMS response time is better than it ever has been, medical procedures are more effective and traffic system design has concentrated on safer roads and intersections. While this has brought about reductions in auto, bicycle and pedestrian deaths, some of that loss was simply transferred over to motorcyclist deaths.
Iow, just as with automobiles, Dyson’s words could be applied to motorcycles. It appears “the number of deaths does not depend strongly on the size of the country, the quality of the roads, the rules and regulations governing traffic, or the safety equipment.”
In this way, Smeed’s Law might be true but in a different way than with cars. When it comes to autos, people are sickened by the death rate and demand change as a nation of drivers—but they keep on driving and registrations keep on going up.
But motorcycling doesn’t behave the same way: in the past three cycles, registrations peaked before fatalities did—but unlike Smeed’s Law predicted, registrations did fall off.
Iow, while drivers either behave more safely or there are changes to design, roads or safety measures are brought to bear, this doesn’t happen with riders—yet the fatality rate still drops. But so does registrations.
It could be that individual riders no longer believe that riding is safe for them and give up motorcycling—and thus increased motorcycle “safety” is really attrition. Which doesn’t make motorcycling safer at all.
[i] Smeed, R. J. Some Statistical Aspects of Road Safety Research. Journal of the Royal Statistical Society. Series A (General), Vol. 112, No. 1 (1949), pp. 1-34.
[ii] Dyson, Freeman. “Part II: A Failure of Intelligence” Technology Review
[iii] Hakamies-Blomqvist, Liisa and Mats Wiklund, Per Henriksson. Predicting older drivers’ accident involvement – Smeed’s law revisited. Accident Analysis and Prevention 37 (2005) 675–680.