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FIGURE 3-1 Safety of travel in the United States: 1989-2007.
SOURCE: Derived from data, used with permission, from Air Transport Association of America, Inc. (n.d.). See http://www.airlines.org/Economics/DataAnalysis/Pages/SafetyRecordofUSAirCarriers.aspx [August 2011]. 1927-1937: AA Statistical Handbook (December 1945). 1938-1971: CAB Handbook of Airline Statistics (1973), Part VIII, Items 19c, d, pp. 595-596; NTSB Safety Studies Division. 19721982: FAA Statistical Handbook (1972-1982), Table 9.3, p. 161, citing NTSB for totals; 1983-present: NTSB Aviation Accident Statistics, Table 6. Fatal Accident Rate excludes incidents resulting from illegal acts, consistent with NTSB practice.

Although measuring safety in terms of fatalities per passenger mile is a useful way of comparing safety across different modes of road travel, it is not the most useful way to measure airline safety.1 For automobile travel, for example, the risk of an accident varies across the types of roads used. Travel on interstate highways is much safer than travel on arterial highways, which in turn are much safer than travel on local roads (National Research Council, 2010, Figure 3-10). Travel on rural roads is more dangerous than travel on urban roads for all highway types. But in all of these categories of highway travel, the risk is roughly proportional to the distance traveled, so that the risk of a fatal accident on a 200-mile trip is about twice the risk on a 100-mile trip. Thus, for highway travel, measuring safety on a passenger-mile basis is a reasonable portrayal of the risk a traveler faces.

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1Transportation safety is usually measured as the ratio of some adverse outcome, such as an accident or fatality, to a measure of exposure such as the number of trips taken or the distance traveled.



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