Tuesday, April 1, 2014

Global Warming Deadly to Motorcyclists

Keeling Curve CO2 levels in ppm (NASA blog site) vs. 
NY Times reported MC deaths as % of total traffic deaths
It has long been known that elevated exposure to CO2 can cause headache, confusion, and lethargy. So it should not be surprising that elevated CO2 in the atmosphere could be leading to the higher percentages of motorcyclists being killed on our roadways, given their lack of protective "cages", i.e., a car chassis in the event of a mishap. Maybe our ideas of threshold levels of CO2 caused impairment have been too high.

Of course, there are other theories as to why motorcycle deaths are becoming more prevalent among total traffic deaths.  This morning (4/1/2014), the New York Times published a graphic in its Science section "Fewer Helmets, More Deaths" and attributed the rapid proportional rise of motorcycle fatalities in the last couple decades to the repeal of helmet laws. A CDC report is quoted, but no numbers are shown that supports that the lack of helmets led to the sharp rise in deaths, i.e., were these fatals primarily due to head injuries? Do the rise in fatals in states repealing helmet laws exceed, statistically, the rise in fatals in "control" states that still have helmet laws? On first glance, the rise in fatals in TX and Arkansas, two states that repealed, looked similar to the national average. Florida was higher.

Meanwhile, in 2010, Dr. Mark Gestring of the Univ. of Rochester Med School/Strong Memorial Hospital trauma center authored a journal article (March, 2010, American Surgeon) where they showed that the demographics of motorcycle crash injuries had changed, with a significant rise in motorcycle crash injuries or deaths in the cotere of middle-aged guys returning to motorcycling after a hiatus, i.e., "Old Guys Returning to Motorcycle Riding" population rather than the "young and fearless" riders who used to keep the meat wagons occupied. The authors suggest the rise in fatals and serious injury in older riders is due to two things, one, the prevalent crashes for the older rider were simple loss of control crashes, perhaps due to a loss of the fine motor skills and senses (seeing, hearing) these returning riders used to have when they were young thus making them more likely to crash (unless the rider consciously compensates for these skills losses), and two, the inability of the old rider to withstand the trauma of a crash that a young person could have withstood with good chances of recovery. Interestingly, the prevalence of helmet use was similar in both older and younger riders involved in crashes requiring hospitalization or the morgue.
Other things are changing as well. Cars and light trucks are constantly re-engineered to protect their occupants.  A motorcyclist is still his own air bag and crumple zone, although current motorcycles have better handling and brakes. OTOH, they have gotten huge and overpowered. Huge, overpowered motorcycles in the hands of older riders with diminished motor skills, poorer vision, and slower reflexes...hmmmm.

I emailed the NY Times asking if they would defend their position that this is all about helmets. One could just as easily plot motorcycle deaths vs. the Keeling Curve (i.e., the concentration of CO2 in the atmosphere as measured at Mauna Loa Observatory) and claim a relationship.

We in the bicycling community often go through our own cycling arguments about correlation vs. causation, not to mention question begging, with topics such as helmets, safety in numbers, facility design, rider position vs. driver awareness, etc. One has to beware of plotting things and claiming cause and effect, i.e., begging the question rather than testing and disproving or finding scientific support for a hypothesis.  I'd love to see the numbers published supporting various great ideas we bat around in the advocacy movement(s).

Stay tuned
Khal Spencer
Member, Old Guys Returning to Motorcycle Riding
April 1st, 2014


Steve A said...
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Victorianne Musonza said...
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