Again, such interpretations of the probability of death through passenger miles can be found anywhere: from Vox or Metro to amateur infographics on Pikabu . Plus, there are naked statements like “How’s the absolute safest way to travel” from Washington Post journalists and other equally famous media.
Most refer to the scientific work of a certain Ian Savage (Ian Savage) of the University of Northwestern. I want to draw your attention to the fact that the key factor of safety in his study is the ratio of deaths and the number of passenger miles. And this is a fair indicator. It is obvious that there are many more people moving on the earth than in the air. But is it fair to compare data on traffic accidents, which are managed by non-professional drivers who violate traffic rules , and specially trained pilots? It would be interesting to compare the safety of buses and airplanes.
Jan Savage has already compared them. It turns out that the bus is almost 70 times safer than a conventional car. But the famous infographics for some reason excludes this fact. And the most interesting as always under the asterisk: in the note to the table it is indicated that the data on the death rate in trains include cases of attack and violence. That is, due to the fact that someone has arranged ponazhovshchinu in the tambour, the safety factor of trains is decreasing. Yes, we do not have exact data and it can only be a percentage of the number of victims on the railway. But maybe the other way around.
Jan Savage operates on data from the United States Department of Transportation . And what is a passenger mile? Let’s imagine that all tickets for London-Sydney to Boeing-747 were sold to Heathrow. If the plane makes a successful landing in Australia, 14.4 million passenger-kilometers (800 pas * 18000 km) will be written in favor of the aircraft . For the wheel back and forth I will have to travel 400 times in order to achieve the same value. With a friend – 200 times. But how can you know and keep records of passengers in private transport? Even if someone conducted a panel survey, then in terms of analytics to use these data to summarize the safety of transport is extremely unprofessional.
By the way, it’s no less unprofessional for me to criticize other people’s works without any argumentation. So, according to the US Department of Transportation , a total of 4473336 million passenger miles for 2015 were recorded on roads ( total, total ) . And according to Statista in the US, about 222 million people have a driver’s license. If you divide the first value into the second, you get ~ 20,000 miles per year, passing one person. It would seem that an adequate annual mileage and everything converges! But we’re talking about passenger miles. In the intercity bus there are about 60 places, in Gazela – 12. There are also services of fellow travelers and fellow travelers. Proportional to the average or median number of passengers in the car will reduce the above-described annual mileage. It is important not to forget that furs, taxis and buses have an annual run many times more.
I emphasize that this post is not a research paper. Data on the rights for 2016, about miles – for 2015. In addition, not all 222 million people drive cars. But if poprikidyvat values, the indicator highway, total causes a lot of questions. Take into account the exact number of passengers by the ways of only rail / aero / sea stations. In private cars, buses, trolley buses is very large error.