Claims that this-or-that highway safety program or this-or-that new idea has had a profound effect on road deaths are commonly very misleading, and a new claim from Alabama undoubtedly comes into this category.
The headline for the article in question, from The Plainsman, is:
New highway safety campaign decreases deaths by over 50 percent
The key fact in such issues is that most crashes have more than one cause (or factor) in their occurrence. Not every country does sufficient scene-appraisal and analysis to correctly assess the relative importance of the various factors but it is probably fair to say that the average is around 2.5 factors per crash.
This means that very few crashes are caused by speed alone (or by any other single cause).
We also know, from NHTSA/NCSA figures, that speed is a factor in 28-29 percent of all fatal crashes in the USA each year — meaning that it is a factor in over 11,500 road deaths per year from a total of ~40,200 (based on year 2016 casualty figures from the NSC).
In the case of the current article from Alabama, there is also the fact that numbers of crashes and casualties can vary very widely. Even though it’s unlikely, pure chance alone, could result in a week entirely without road deaths. So who would claim the credit for that? Experts will tell you that even comparing one year to the next is very unreliable and that trends over a period of several years need to be studied in order to learn anything significant.
So here’s the first question: How is a speeding campaign, focused on a relatively small number of roads in the state, going to prevent, for example, fatal crashes on all other roads in the state, especially ones caused by — say — distracted driving, alcohol, a badly-maintained vehicle, a driver failing to see a pedestrian or cyclist, etc.?
Don’t get me wrong. I’m certainly not claiming that campaigns such as this anti-speeding program in Alabama are wrong or ineffective; they are not, they are good and certainly do reduce deaths. But to aim for zero deaths in any given period of time, solely because of an anti-speeding campaign, is frankly naïve, and if — by nothing more than good fortune — there had been zero deaths during the week in question, then to claim that this happy fact had been entirely due to that campaign would frankly have been both inaccurate and very misleading.
The most overwhelming examples of wildly inaccurate claims occurred in the first 2-3 years of the 2008 financial crisis, at which time people from all areas of highway safety — the law enforcers, road engineers, vehicle engineering, educators and so on — were claiming that their latest programs were having amazing effects on cutting road deaths. Yet all of them were conveniently choosing to ignore the fact that in times of recession the number of road deaths always drops dramatically because the amount of road travel drops dramatically, due to reduced business travel, fewer deliveries, heavy unemployment and lack of money for road trips, and this creates lower “exposure to risk” and the said drop in numbers of crashes and deaths.
Shame on the people who made such ridiculous “haven’t we done well” claims. It is, of course, a fact that none of them spoke to the press to claim responsibility in the very recent years when the number of road deaths in the U.S. have been and still are catapulting upwards once more. All of a sudden, this is apparently somebody else’s responsibility!
Any work in road safety requires (a) that people who speak or publish things on the subject need to be genuine experts who truly know what they are talking about, not just guessing or using outdated or inaccurate bases for their so-called facts, and (b) they must not exaggerate or make speculative claims.
Unfortunately, here in America, the opposite is far too often the case and the public have no idea of how bad the situation really is.