American Drivers: Knowing and Doing

By Edward Tenner

With the Memorial Day weekend and the summer holiday season arriving, you might be wondering what's a safer place to drive, the Big Sky roads of Montana or the scary parkways of New Jersey, after reading the ABC News online story on the results of a GMAC Insurance survey, "Top States with America's Worst Drivers."  It suggests the wide-open spaces are a safer bet. Idaho, Wisconsin, and Montana drivers were best informed, in that order, and New York, New Jersey, and Hawaii motorists scored lowest.

After enough close encounters on the roads of the Northeast, and scenic bliss in Montana, I'd be inclined to endorse the survey's results. There's just one problem. According to most recent official data of the Census Bureau's Statistical Abstract of the United States, New Jersey is actually the sixth safest state, with only 1.0 fatalities per 100 million vehicle miles, while Montana is the riskiest, with 2.3 deaths. New York State is about as safe as New Jersey. Idaho, the top state for knowledge, is slightly more dangerous for motorists than Hawaii (1.8 vs. 1.6 fatalities). Wisconsin might be your best all-around bet as the runner-up for driver information and 1.2 deaths per hundred million vehicle miles, just making the top quarter of safety rankings. But it's still 20 percent more dangerous than New York or New Jersey.

The automotive safety analyst Dr. Leonard Evans writes in the first edition of his standard Traffic Safety and the Driver:

[W]e find no convincing evidence that driver education, or increased driving skill and knowledge, increase safety.

And he continues:

Few would suggest that criminal activity flows from insufficient study of ethics, and that instruction in this discipline would much reduce crime.

The paradox is that the densely settled Northeast is generally a safer place to drive than the rural West because 1) severity of accidents depends greatly on speed, and our frequently crawling traffic is thus extra safe, and 2) when it is moving it often feels and looks dangerous, so we're more alert. Drivers in the rural West have much longer journeys between settlements and more incentive to go as fast as they can.

The British aeronautical engineer and statistician Reuben Smeed was the first to analyze the process mathematically. Smeed's admiring wartime employee in the RAF Bomber Command, Freeman Dyson, has written of his mentor's postwar renown as Britain's leading traffic engineer:

He collected statistics on traffic deaths from many countries, all the way back to the invention of the automobile. He found that under an enormous range of conditions, the number of deaths in a country per year is given by a simple formula: 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. This formula is known as Smeed's Law. He published it in 1949, and it is still valid 57 years later.

In other words, the more people drive, the fewer fatal accidents per hundred million miles they suffer. The most dangerous place of all to drive is in a developing country with open roads and low density of car ownership.

Getting back to the GMAC study, only one of GMAC's own list of five major causes of crashes relates directly to a question on the test. Take the  test and then read Top Driving Mistakes that Cause Crashes and see if you agree with me. While I have a few reservations --  I'll withhold them to avoid spoilers -- the driving tips are generally excellent and could save lives. But most of the aggressive and just plain bad driving I've seen, everywhere, seems to have arisen not from ignorance of the rules but the conviction that they're only for other people.

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