Which is safer? Flying or driving?
Jul 24 2014
For driving, the national highway traffic safety administration (NHTSA) compiles and researches accident statistics in the US. Data from its 2008 report titled ‘Traffic Safety Facts’ boils down the millions of accidents and other statistics to 1.27 fatalities per 100 million vehicle miles travelled. In contrast, the 1998 rate was 1.58 fatalities per 100 million miles. Thus, the fatalities per 100 million miles have come down in a decade for driving.
For flying, the National Transportation Safety Board (NTSB) compiles aviation accident data. Preliminary statistics for 2008 show only 20 accidents for US air carriers operating scheduled service. This works out to nearly zero accidents per million flying miles. Here, no one died, and only five people were seriously injured.
Thus, in absolute numbers, driving is much more dangerous, with more than 5 million accidents compared with 20 accidents in flying in 2008 alone. A more direct comparison per 100 million miles pits driving’s 1.27 fatalities and 80 injuries against flying’s lack of deaths and almost no injuries, which again shows air travel to be safer.
Furthermore, the US National Safety Council compiles an odds-of-dying table, which further illustrates the relative risks of flying and driving safety. In 2008, it calculated the odds of dying in a motor vehicle accident to be one in 98 for a lifetime. For air and space transport, the odds were one in 7,178 for a lifetime, according to the same table. Thus, odds-of-dying table also makes flying safer than driving.
Still, one may argue that the number of deaths involved in flying changes from year-to-year with some years involving no deaths at all and other years involving a significant number of deaths. So, how does the historical average look like? Even if we average the past 20 years of data, a range that includes the 9/11 attacks and several other large American aviation disasters from the mid-90s, there are 1,598 deaths over a total of 143 billion miles flown by US carriers alone. This works out to 1.11 fatalities per 100 million miles travelled by airplanes, which makes flying still safer than driving.
However, flying may feel more dangerous because public risk perception is based on more than facts and numbers. First, driving affords more personal control, making it feel safer (a bias called illusion of control). In addition, plane crashes are catastrophic, killing more people at once, which grab more attention and make people more sensitive to them. Car crashes happen every day and spread the loss over time, making their combined effects less noticeable. Thus, our risk perception is more tuned to those available items that appear in news (airplane disasters) compared with those that do not make it to the news (automobile disasters).
In support of the above argument, Gerd Gigerenzer, Max Planck Institute for Human Development, Germany, examined US travel data before and after 9/11 to see how the terrorist attack affected travel behaviour. He found that in the year following the 9/11 attacks, people flew less: the amount of miles travelled by plane dropped between 12-20 per cent compared with the year before. During the same time period, people drove more (especially in a way that would compensate for plane travel): the amount of miles travelled in cars on interstate highways increased between 2.2-5.7 per cent. Compared with the years before and the years after, he estimated that there were an extra 1,595 deaths from car accidents in the year following 9/11, more than 17 times the number of air travel deaths (83) in 2000 in the US. These numbers of death were a result of the extra driving that people did instead of flying.
Humans are not purely rational and for them, the anxiety caused by flying exceeds that caused by driving. Well, humans are bombarded by fear every time they turn on the news about air accidents. So isn’t this the fault of the media to make us fearful? Media sensationalism certainly plays a part in getting people hyped up over rare risks; after all, tragedy makes for good television viewership. But one would argue that while the outcome of MH 370 remains a mystery, the probability of a similar event occurring is astronomically low. However, these stories are covered in ways that influence our unconscious biases and emotional self. After hearing about the victims, their daily lives, and their tragic loss, we feel that we know them. It is a fact that we empathise easily with individuals, but we have trouble personalising numbers and statistics.
So what’s the bottom line? It might be impossible to escape how our minds think about experiences versus statistics and numbers. However, it is possible to recognise our mind’s limitations for salient experiences and try not to act on them. As individuals and as a society, maybe that’s the best we can do.
(The writer is on the faculty of Indian Institute of Technology, Mandi, India)