The study is described in the paper "Safe at Home? An Experiment in Domestic Airline Security," which appears in the latest issue of the journal Operations Research, an INFORMS publication. The experiment concerned positive domestic passenger bag-match, a policy under which no bag would travel in a luggage compartment unless checked in by a passenger known to be on the flight.
[An abstract of the study is at http://www2.informs.org/Press/ppbmabstract.pdf . Professor Barnett's January, 2002 testimony on this subject is at http://www2.informs.org/Press/congressionaltestimony.htm ]
Bag match is already the policy in Western Europe and on all international flights. An unaccompanied suitcase is believed responsible for the destruction of Pan Am Flight 103 over Lockerbie, Scotland in 1988.
The unprecedented test in May 1997 involved two weeks, 11 US airlines, 8000 flights, and 750,000 passengers. The Operations Researchers — Arnold I. Barnett and Amedeo Odoni of MIT, Robert Shumsky of the University of Rochester, and Mark Hansen and Geoffrey Gosling of the University of California Berkeley — concluded that:
- 100% matching of bags to passengers would cause departure delays to about one in seven US domestic flights and, when they occur, such delays would average seven minutes apiece. Thus, the frequent flier would encounter delays averaging one minute per flight.
- The dollar cost of implementing 100% matching would be approximately 40 cents per passenger emplanement.
- 100% bag-match would entail virtually no reduction in the number of flights.
- The revised baggage-handling procedures associated with the security measure would substantially reduce the number of lost and mishandled checked bags.
Under existing security procedures, 5% of passengers chosen by computer are subject to bag match. The study estimates that this measure already causes departure delays that average 15 seconds per flight, and cost about 20 cents per emplanement. Thus, the extra cost in moving from 5% to 100% bag match would be about 45 seconds per departure and 20 cents per enplanement.
Professor Arnold Barnett, who chaired the FAA’s technical team on bag-matching, sees the policy question as follows: Is it worth 20 extra cents and delays averaging an extra 45 seconds apiece (which, in rare instances, would be as long as ten minutes) to reduce greatly the number of unaccompanied suitcases on US aircraft?
"No one knows," he acknowledges, "what security benefits, if any, would result from the policy shift, just as no one knows how many Tynenol-type poisonings have been averted by the protective shields that have appeared on grocery items for the past 19 years, costing billions of dollars and billions of person-hours of extra time opening packages. But given the modest additional costs of 100% bag match, many passengers might support that measure even if there is only a chance that it would be beneficial."
The bag-match experiment involved a sample of about 4% of all US domestic routes in a variety of categories, including existing bag-match routes, shuttle routes, transcontinental routes, high-frequency hub-spoke routes, and low-frequency hub-spoke routes. Detailed calculations considered the extent to which a bag-match flight delay could induce delays on subsequent flights, as well as the extent to which adaptations by both passengers and airlines could reduce the initial delays after bag-match is first introduced.
The researchers are all affiliated with the National Center of Excellence in Aviation Operations Research (NEXTOR), an industry-academic-government team created by the FAA in 1996.
The study did not consider explosive detection technologies, which could make bag-match unnecessary if they confirmed that no suitcases loaded onto aircraft could contain bombs. However, said Prof. Barnett, the use of such detectors to screen all US checked luggage is many years and perhaps decades away.
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