New study claims global warming caused 2015 spike in road deaths

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This is why global warming activists have little credibility: A new study has concluded that global warming, not increased use of cell phones, caused the increased number of road deaths in 2015.

Combining government data for the 100 most densely-populated U.S. counties for miles driven, vehicle fatalities and weather, researcher Leon Robertson found that motorists clock up extra miles as temperatures and precipitation rates rose. When temperature rose by a degree Fahrenheit (0.5 Celsius), vehicles were driven an additional 60 miles (95 kms) per person over a year, Robertson said in the study, which was published in the academic journal Injury Prevention.

Using mathematical models, the retired Yale University epidemiologist also found that for every additional inch (2.5 cm) of rainfall, cars and trucks racked up an average of 66 more miles (105 kms) per motorist for a year. Hotter than normal outdoors temperatures likely accounted for most of the extra deaths in 2015, Robertson said.”If millions more people drive cars because the temperature is getting warmer … then that adds up to a lot of miles,” he told the Thomson Reuters Foundation.

“Mainly it’s a simple multiplication.”

Since road deaths apparently dropped in 2016, does this mean that global warming has ceased?


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  • Commodude

    Correlation doesn’t equal causality (I know, on this site I’m preaching to the choir with that statement…)

    Common sense would dictate that as weather (in theory) worsens, miles driven actually fall, as people stay home more to stay out of the slop.

    They’re getting comical.

  • wodun

    There is probably a stronger correlation between gas prices and the number of people on the road.

    An imperceptible change in temperature is unlikely to cause a subliminal desire to travel. Just as wetter weather is unlikely to cause a subliminal desire to travel. Lower gas prices can affect the conscious decision making process though.

  • wayne

    good stuff.

    The amazing thing about auto-deaths, an actual fact, we drive more miles & less of us die in absolute numbers, doing it.

    tangentially– ironically, the introduction of safety-glass, seat-belts, anti-lock brakes, and traction control systems, tend to encourage people to drive more aggressively.

  • Mike Borgelt

    More evidence that academia needs to be radically down sized. About 10% of the current size would seem about right.

  • Joe

    Temperature and amount or type of precipitation matter not in an age when you can control the environment in your vehicle to the extent that is possible inside of modern interiors, if I want to go somewhere I do. If people would just look outside of their cars and pay attention to what is going on around them, many of the advancements in auto safety would be a moot point.

  • Wayne: I am trying to respond to an email you sent me, but the email keeps bouncing unsent with this error message: “An error occurred while sending mail: The mail server sent an incorrect greeting: 4.3.4 allocated resources exceeded.” This suggests that your mailbox is full.

  • Edward

    Reading the abstract (I chose not to buy the report), I find that the author only pondered weather-related phenomena, specifically temperature and precipitation. He is attempting to relate a trend change of a 7% increase in traffic deaths in the USA due strictly to weather and avoids consideration of all other variables. He does not seem to associate these deaths with any other possible cause and notes a world-wide (not nation-wide) increase in urban (only) per capita miles driven with increased temperature then assumes the world-wide relationship should correspond with a USA-specific relationship.
    Here I test the hypothesis that weather influenced the change in [the 35-year downward] trend.

    However, he does not seem to test the hypothesis with any other possible cause for increased traffic deaths. He notes a 35-year trend of decreasing deaths, but that is just a trend. Presumably other years have also had death rates that also were above or below a least-squares trend line, but unlike 2015, those do not seem to be considered anomalous. Is the 7% deviation within normal variation? He also does not seem to make comparisons with any other years, such as 2013 or earlier. In essence, he draws conclusions from a single data point.

    But the funny thing is, NOAA and NASA reported 2015 was not so very much warmer than 2014, certainly not enough to account for a 7% increase in deaths in the USA. If it could account for such a dramatic increase, then with the warming trend from around 1980 to around 2000 — and especially now that NOAA and NASA have “discovered” (read: “fudged the data”) that there was no warming “pause” after 2000 — shouldn’t the 35-year trend have been of increasing traffic death rate, not a decreasing rate?

    I can only wonder whether or not his results merely show that urbanites tend to rush out to the park to celebrate the beginning of spring, as I noted when I lived in snowy regions. Certainly, Americans and Europeans drive more during summer holidays than during the winter workdays, and I would not be surprised if the peoples of the rest of the world react similarly to the changing seasons. Could the conclusions, based solely on temperature and precipitation, merely reflect a seasonal change in driving habits rather than a global-warming climate-change anthropegenic-disaster whatever-thingy cause of changes in driving habits?

  • wayne

    Good stuff.
    I didn’t even make it through the Abstract, so thanks for plodding through it.

    These people are data-mining with a pre-conceived outcome, I’d be surprised if they didn’t come up with all sort of spurious correlations.
    It’s a “figure’s don’t lie but liar’s always figure” sorta deal.

    One thing for certain, absolute deaths have declined while miles-driven have steadily grown.
    ( Accidents were less-survivable compared to today, most deaths in the 1960’s for example, were blunt-force trauma– car interiors were considerably more deadly. And.. road engineering has gotten a lot better, not to mention cars themselves.

    Take a look at the Wiki entry I reference above. Then head to the Highway Traffic Safety Administration for everything you would ever want to know about auto-fatalities.

  • Edward

    Thank you, wayne, for reminding me about the Wikipedia link; in my excitement to comment on the post, I had forgotten to look at your link before starting to write. It has a table showing that 2015 was a year with an abnormally large spike in fatalities, answering my question that the year was a bit outside the normal variation in fatalities.

    The 1960s were when auto makers began to take safety more seriously; before that, they didn’t want people to think that cars were unsafe, despite everyone already aware of that sad fact. In that decade, seat belts came onto the market. I remember that my father had seatbelts installed into the family car (it may have been a factory option or he may have had a retrofit, I don’t remember that detail).

    Child seats, back then, were a joke. My baby brother (somewhat more grown up, now) had a child seat that fit over the front-seat couch. It had no restraints, but it did have some padding, which would only help during a tire-squealing stop, not a crash, and it had a little steering wheel for him to play with, which would have hurt his chest, had we crashed.

    The book “How To Lie With Statistics” is still available, after all these decades, and it can help in spotting some of the tricks that are used to draw people to the wrong conclusions. (We had a couple of recent threads, here at BtB, with links to web pages in which other tricks had been used, apparently successfully, to try to get some people to draw the wrong conclusions. However, that is another topic best left for another time in the far, far distant future.)

    Don’t worry about not making it all the way through an abstract. They are dry, boring overviews describing the rest of the paper in order to let other scientists know whether or not the paper is what they are looking for as part of their research into whatever related or unrelated topic they are working on at the moment. If you made it through that last sentence, then maybe abstracts are for you after all.

  • wayne

    Good stuff.

    Motor vehicle deaths 1900-2015:

    The best period to use, is 1950-present. Road construction increased dramatically after WW-2 and peaked with the building of the Interstate system.

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