But Isn't Flying Safer than Driving? -- A Reply

By Edward Tenner

Kylefree comments on my post on air safety:

I think improving airline safety is a poor allocation of resources. If the airline/aviation industry focused instead on lowering costs, fewer people would drive, saving more lives. How many people a year die because it was cheaper to drive than fly?

The comparative safety of aviation over driving is based on fatalities per million passenger miles. But most of the risks of flight are on takeoff and landing. According to one air safety site, only 12 percent of fatalities occur while cruising; the rest happen on or shortly before or after takeoff or landing, respectively. See this summary from Wikipedia, emphasis added:

There are three main statistics which may be used to compare the safety of various forms of travel:

Deaths per billion journeys:
Bus: 4.3 Rail: 20 Van: 20 Car: 40 Foot: 40 Water: 90 Air: 117 Bicycle: 170 Motorcycle: 1640

Deaths per billion hours:
Bus: 11.1 Rail: 30 Air: 30.8 Water: 50 Van: 60 Car: 130 Foot: 220 Bicycle: 550 Motorcycle: 4840

Deaths per billion kilometres:
Air: 0.05 Bus: 0.4 Rail: 0.6 Van: 1.2 Water: 2.6 Car: 3.1 Bicycle: 44.6 Foot: 54.2 Motorcycle: 108.9

It is worth noting that the air industry's insurers base their calculations on the "number of deaths per journey" statistic while the industry itself generally uses the "number of deaths per kilometre" statistic in press releases.


The above is based on late 1990s statistics. I don't think the pattern has changed significantly but I'd welcome links from readers to more recent data.

Automotive risk depends on many factors, including the driver's capabilities. More frequent rail and bus service are clearly the best solution, but the defensive, sober, undistracted motorist is even safer than the statistics suggest. We need more sophisticated analyses showing when the greater cruising safety advantages of flying offsets the hazards of takeoffs and landings, including bird strikes. Coast to coast, airline travel beats jockeying with 18-wheelers over mountain passes. But for many shorter journeys, dread of driving can be as irrational as fear of flying.


This article available online at:

http://www.theatlantic.com/technology/archive/2009/08/but-isnt-flying-safer-than-driving-a-reply/22992/