Airline Passenger Security Screening: New Technologies and Implementation Issues (1996)

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8
Public Acceptance

The public acceptance issues associated with new passenger screening technologies focus on the extent to which people are willing to tolerate the screening procedures. While a screening technology and its operator may function properly, the ultimate success of the procedure requires its acceptance by the people being screened. The term people does not refer to a homogeneous body but to a group that includes airline passengers, friends and relatives of passengers, flight crews, and airport and air carrier employees. Some people are exposed to screening infrequently, while others are screened more often. Thus, these two groups may react quite differently to the implementation of a new screening technology.

As discussed in the introductory chapter, the concerns of people exposed to screening technologies can be expected to fall under four broad categories: health (exemplified by concerns about exposure to radiation), convenience, privacy (encompassing both possessions and the person's body)1 and comfort. Public acceptance of the passenger screening technologies described in chapter 3 will also depend on the extent to which they are viewed as successful in providing security and on the degree to which that security is seen as necessary.

PUBLIC CONCERNS ABOUT HEALTH EFFECTS

The health issues associated with the technologies under consideration are discussed in chapter 6. Health concerns over active imaging technologies and over dielectric portals result more from negative perceptions of risk than from actual health threats. Although the technologies do not pose a health problem, people may believe that they do. This perception may be strong especially among aircrews and airport employees exposed to frequent screening as part of their employment. Such perceptions of risk may be addressed effectively by providing information regarding the insignificant exposure levels involved in the technologies. However, the information must be presented in a way that is understandable to a wide variety of audiences. Comparing radiation doses used in passenger screening to greater, but still safe, doses used in common or familiar procedures usually is a meaningful and

effective approach. Such information should be presented at the screening site, perhaps as part of a public education effort.

Health concerns over trace-detection technologies center on potential disease transmission through contacts either between individuals or between people being screened and the equipment. Although the health hazards appear insignificant, the screening equipment should be designed to allow frequent cleaning to minimize passenger-to-passenger disease transmission and the public perception of an unhealthy environment. Health concerns related to nonimaging electromagnetic portals have more to do with risk perception than with actual health threats. Again, in the context of such technologies, public perceptions can, and should, be addressed through public information and education.

PUBLIC CONCERNS ABOUT PRIVACY

Privacy is likely to be the most significant public acceptance issue associated with imaging technologies. Displaying an image of the body on a monitor will obviously be of concern to a significant percentage of people passing through screening checkpoints. This concern may be greater among flight crews and airport employees who are screened more frequently and who may be known to or familiar with the operators. It is important to address this concern before imaging technologies can gain acceptance. Steps to alleviate concerns may include:

·      masking portions of the displayed image or distorting the image to make it appear less ''human"

·      using operators of the same sex as the subject to view the images

·      displaying the images out of the view of everyone except the screening personnel

·      providing guarantees that the images will not be preserved beyond the brief screening procedure, except when questionable objects are detected

·      offering alternative screening procedures for those who object to imaging

Privacy concerns associated with trace-detection technologies appear to fall into two categories. The first category involves concerns over information revealed in the screening

1 As a general rule, privacy is a more significant issue for women than for men.

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process that subjects may wish to keep private, such as the presence of a medical device or the use of nitroglycerin or other medications. To address these concerns over privacy, trace-detection technologies should be adapted, as specifically as possible, to the threat being investigated.

The second category involves the aversion of some people to being touched, either with an inanimate object, such as a bar or a frond, or by a person wielding a hand-wand device. This concern is more difficult to address because the desire to maintain distance from strangers is a deeply ingrained response that is often influenced by basic cultural and religious beliefs. The optimum distance that people preserve between themselves and others varies greatly from person to person and from culture to culture, and it is unlikely to be swayed by public information campaigns. For procedures requiring contact between the screening personnel and the person being screened, it is important for the screener to maintain a professional attitude. Same-sex screening would probably make the procedure more acceptable to some people. For technologies requiring passengers to touch a piece of equipment, passenger acceptance may be enhanced by allowing subjects to control the area to be touched (e.g., letting them push doors open with their hands), instead of having them walk through a portal lined with fronds that brush against the entire body. The former approach, however, will restrict sample collection significantly and could result in less effective screening.

Because nonimaging metal-detection portals are already being used in airports, the panel does not expect concerns over privacy, beyond those that may exist today, to emerge from the use of improved versions of this technology. The nonimaging dielectric portals, similarly, would raise few concerns about privacy. Indeed, if the technology could be made more specific to detecting threat objects, then passengers would be less concerned about invasions to their privacy. For example, people would no longer be forced to empty their pockets at the security checkpoint.

PUBLIC CONCERNS ABOUT CONVENIENCE

As noted earlier in the report, convenience is largely a matter of time. Given that people in airports are often in a hurry and concerned with time, screening technologies that impose delays will have problems with public acceptance. Carry-on baggage screening technologies currently impose a delay of approximately six seconds, in addition to any time spent waiting in line to place carry-on bags onto conveyor belts. Technologies able to process people in six seconds or less are not likely to be a problem because passengers are already accustomed to such time delays. Nonimaging electromagnetic and microwave technologies are consistent with this time goal. Current uses of the imaging technologies under consideration (e.g., for screening persons entering correctional facilities) do not impose time constraints. However, it is not known whether these technologies can be used to screen a passenger in approximately six seconds, including time for creating and interpreting the image. Trace-detection technologies, especially the sampling techniques under consideration are much less mature in the area of passenger screening, and the ability of these technologies to meet the six-second goal is unknown.

PUBLIC CONCERNS ABOUT COMFORT

Issues related to comfort will generally arise for technologies that require people to be in close contact with either the equipment or with other people; people usually do not like to be touched. For example, implementing a technology that requires a passenger to stand in an enclosed space for screening is likely to cause comfort concerns. Technologies that involve touching a person with an object, such as walking through a portal lined with fronds that brush against the body, may also make people uncomfortable. However, giving people more control over the area to be touched, such as allowing them to push a door open with their hands, may cause less apprehension.

Imaging technologies or nonimaging electromagnetic and microwave technologies implemented in an enclosed area might raise concerns over passenger comfort, but trace-detection technologies are more likely to cause such concerns because they require either physical contact or confined airflow. Technologies that incorporate physical contact between the person being screened and the equipment or the human operator will probably raise more concern over comfort than those that do not. Current implementation possibilities for trace-detection technologies include contact portals and hand-wand devices. Portals necessitate close contact between the person being screened and the screening equipment; hand-wand devices require close contact between the person being screened and the screening operator. As with the privacy issues, the comfort issues associated with contact trace technologies may prove to be a significant implementation hurdle because the desire to keep an optimum distance from other people and objects is deeply ingrained. The optimum distance depends on a wide variety of factors, including culture, gender, and status and is unlikely to be altered by a public education campaign.

Technologies that collect samples by using airflow rather than through physical contact will create less apprehension, but they may not be as effective as technologies that require contact. Technologies that can take advantage of a secondary source of particulates (e.g., by analyzing boarding passes or the handles of carry-on bags) would also be more acceptable to the average passenger than technologies that require physical contact.

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ASSESSING PUBLIC ACCEPTANCE

The analysis of public acceptance issues is based on the work of the panel, as outlined in chapter 2, the methodology section. Further efforts to assess public acceptance of a particular technology and to incorporate this information into the screening system using that technology will be necessary to ensure effective performance.

Conducting the assessment presents a relatively complex and difficult problem. The degree to which people will accept the inconvenience, discomfort, delays, embarrassment, real or perceived health risks, and the real or perceived invasions of their privacy associated with passenger screening depends on the interaction of several variables. The variables that affect public acceptance of specific screening systems and procedures include the following:

·      the nature, extent, and likelihood of the actual threat and the associated risks

·      the degree of understanding and the perception of the actual threat and the associated risks

·      personal beliefs, habits, and cultural mores

·      the physical, mental, and emotional state of an individual

·      the extent and degree of public understanding of the screening objectives, technology, and procedures

·      public perception of the effectiveness of the screening system

·      public understanding and perception of the health risks associated with the screening system

·      the nature and frequency of air travel

One way to assess public acceptance of alternative screening systems and procedures is to conduct a survey of the population most likely to be affected by passenger screening. However, obtaining useful, definitive results from such a survey involves significant difficulties because of the potential extent of sampling and measurement error. Sampling error, or the extent to which the sample selected for measurement differs in significant ways from the population sampled, may be substantial due to difficulties in determining the relevant dimensions of the population and the difficulties of sampling the population, once it has been identified. Measurement error, or the extent to which error is introduced by the measurement process itself, is likely to be great due to the difficulties people have in responding to abstract, future (as opposed to concrete, here-and-now) circumstances.

We can identify important issues of public acceptance by identifying similar or analogous circumstances of the past and studying available information on public reaction to, and acceptance of, these circumstances. For example, we can gain insight from the public reaction to, and acceptance of, metal detectors and baggage screeners when they were first introduced. The more recent introduction of imaging screening systems that see through clothing and display images of the bodies of individuals entering correctional institutions can serve as the basis for gaining insight on issues associated with public reaction to, and acceptance of, this passenger-system interface.

Definitive estimates of public acceptance, however, must await the experimental field evaluation of prototype systems. Consequently, it will be important, as part of these field experiments, to include measures of public reaction and acceptance using measurement instruments that have been designed and tested by professionals with expertise in psychometrics.

RESULTS OF THE WORKSHOP ON NEW TECHNOLOGIES FOR PASSENGER SCREENING

The specific concerns identified during the workshop described in chapter 2 are summarized in tables 8-1 and 8-2. In preparing the tables, the possible passenger-system interfaces were first specified for each of the three principal screening technologies currently under consideration—imaging, trace, and nonimaging electromagnetic. Then, the health, privacy, comfort, and convenience concerns identified in the workshop were listed for each interface. Some of the categories of concern are not applicable to a particular technology; for example, the effects of radiation on the body would not be a concern under any of the trace-detection technologies.

The people invited to participate in the workshop represented a variety of organizations with an interest in passenger screening technologies, either because they have responsibilities in the implementation of the screening systems (e.g., air carriers and airports) or because they represent people who interact with these technologies on a regular basis (e.g., flight attendants). The workshop participants were all familiar with the operations of a passenger screening checkpoint and with various technologies considered in the past for use in passenger or baggage screening. Therefore, the reactions of these participants to the new technologies are not broadly representative of the reactions of the general public, who are not likely to be as technically literate or as highly motivated to find better technical solutions to the problem of ensuring airport security. As new technologies move closer to the stage where answers to specific implementation issues will be needed, the concerns expressed in the workshop can be used as guidelines to aid the FAA in identifying appropriate groups and appropriate questions to obtain information about a particular technology.

Health Effects of Radiant Energy from Imaging Technologies

A principal concern expressed early in the workshop was the potential effects of radiant energy from imaging technologies on the body, particularly in cases of pregnant women.

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TABLE 8-1  Principal Concerns Associated with Health and Privacy, as Identified at the Workshop on New Technologies for Passenger Screening

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TABLE 8-2  Principal Concerns Associated with Comfort and Convenience, as Identified at the Workshop on New Technologies for Passenger Screening

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Information presented on the small amounts of radiation involved in the application of imaging technologies, relative to amounts from other sources, appeared to allay these concerns. Specific information on comparative radiation dose levels associated with specific concerns, such as the effects on pregnant women and on pacemaker devices, will be required before these techniques can be implemented.

Displaying Images of the Bodies of Subjects

In the opinion of the workshop participants, imaging technology that requires a human inspector to view the image of a passenger's body is likely to face considerable opposition from passengers, unless steps are taken to assure anonymity and unless the level of threat is perceived to be relatively high. During the workshop, several solutions were offered to make such screening more acceptable:

·      Ensure that the inspector is of the same sex as the passenger being screened.

·      Ensure that the inspector is situated so the passengers and inspectors cannot see each other directly.

·      Mask or eliminate sensitive areas of the passenger's body from the display, if this can be done without reducing the effectiveness of the screening.

·      Represent body parts on the display in a way that reduces recognizability without reducing the effectiveness of the screening.

·      Display the image only if a human inspector is needed to resolve an automatic detection alarm.

Most workshop participants said they would accept the invasion of privacy that these imaging technologies would require if the level of threat were high. Quantifying the threat level at which these technologies would be acceptable for general screening is a difficult task. This is an area that the FAA will need to explore if these technologies prove to meet other requirements for successful implementation.

Possible Unlawful Search and Seizure

A concern expressed during the workshop was that all passenger screening was in violation of the Fourth Amendment to the Constitution of the United States. As noted in chapter 7, the courts have not reached a clear consensus on the legality of these searches. However, in general, the courts have weighed the balance between the individual's right not to be searched without particularized probable cause against the public's right to be protected from air piracy and have decided in favor of the air carriers and the FAA. There was further concern that the searches could go beyond the specific stated objective of passenger screening, that is, the detection

of firearms, explosives, or other items of danger to the aircraft, crew, and passengers. In the extreme case of providing only for aircraft safety, a law enforcement officer called by security personnel to investigate a questionable item, which is later determined to be illegal drugs and not a threat to the aircraft, should ignore the presence of the drugs because they were not the object of the screening. The courts have not supported disregarding evidence of criminal behavior once a person has been stopped in an airport security checkpoint for the possible possession of a threat object. There are many sides to this debate, and new screening technologies are not likely to allay concerns about government surveillance of the innocent act of boarding an airplane.

Time Required for Passenger Screening

It was the consensus of workshop participants that the sensitivity and vulnerability of the entire air transportation system to procedures that will significantly hinder passenger progress through the system was more important than other concerns about passenger acceptance. According to air carrier, airport, and security services representatives, the complexities and interdependencies of the system are now of sufficient magnitude that a delay lasting a few seconds in the screening of an individual passenger can lead to a significant reduction in system efficiency and increases in system costs.

One side effect of the need to maintain acceptable levels of passenger throughput is the potential for less effective screening during times of high passenger volume. According to one workshop attendee, long lines at current checkpoints that use metal-detection portals and carry-on baggage screening systems bring pressure from management personnel to move people through more quickly, thus making it more difficult for the screening system to function effectively.

SOME POSSIBLE PUBLIC ACCEPTANCE CONCERNS ASSOCIATED WITH SPECIFIC SCREENING TECHNOLOGIES

Imaging Technologies

Active imaging technologies involve the use of electromagnetic radiation, such as x-rays, to produce images of individuals and objects that may be concealed under clothing. The use of any type of electromagnetic radiation, regardless of the dose applied, will raise concerns about possible biological damage due to radiation. As discussed earlier, the radiation doses used for any of the screening technologies being investigated are smaller than the amount of radiation received from  many common and commonly accepted sources. This information needs to be communicated to passengers and security-screening checkpoint operators to

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enable them to put the risks of the screening procedure in perspective. However, this public education effort will need to consider that people distinguish between radiation received voluntarily (in medical circumstances or transcontinental flights) and radiation received involuntarily (from living in areas built over uranium mill tailings or receiving fallout from nuclear weapons tests). Passive imaging technologies are not likely to generate any health concerns because they scan for radiation naturally emitted by the human body.

In addition to concerns over the biological effects of radiation, people will be concerned with privacy issues related to the exposure of the images of their bodies. People will want to know who will see the images and how the data from the images will be handled. Using operators of the same sex to view the image and situating the operator in a remote location (far from the individual being screened) will increase public acceptance. However, these measures to accommodate the public will create implementation problems. Same-sex viewing will require more operators than currently employed. In addition, moving the operator to a remote location will require more space and additional personnel because a separate operator also must be stationed at the checkpoint to help resolve alarms and to direct passengers through the system.

Since imaging technologies use data to create an electronic image of a person, that data could be manipulated to make the image appear less human. This could be done perhaps by rearranging the body parts on the screen or by distorting the image to make the body appear unnaturally tall and thin. This type of distortion, achieved by distancing the image from the actual person, might make these technologies more acceptable to people who object to having images of their bodies displayed. People trained to detect threat objects on this type of distorted image may be effective screeners. Research into how much image distortion is feasible, without compromising screening effectiveness, may yield answers to help improve public acceptance of imaging technologies. Assurances must also be given that the data used to create the images will not be archived in any way and will be erased as soon as the person has been cleared to enter the secure part of the airport.

Another possible concern associated with imaging technologies is the revelation of external medical devices worn by some people. These devices will appear on the images and may even call the attention of an operator because they could be used to conceal a threat object. For these people, it may be essential to have a remotely located screener and to have the image displayed as privately as possible.

Imaging technologies may be slower than current screening techniques, especially if multiple views are required. Increasing the time needed to screen each passenger will result in added passenger inconvenience as long lines and longer waiting times become common in airports during peak periods. Air carriers and airport operators will resist the implementation of any technology requiring them to add space for passengers to stand in line at screening checkpoints or to add more checkpoints to keep waiting time to a minimum. Passenger waiting time and delay will be minimized if these technologies can be implemented in such a way that the screener immediately has a 360^° view of the person being screened. However, passengers are likely to object if obtaining the view means screening the subject in an enclosed space.

Trace-Detection Technologies

The use of trace-detection technologies in passenger screening settings may involve person-to-person contact or direct contact between the detection equipment (e.g., trace-chemical sensor) and the individual. As discussed earlier, this contact can lead to concerns over the possible transmission of disease as a result of the contact. Passenger acceptance will be affected by the appearance and cleanliness of the equipment. Few privacy concerns have been associated with trace-detection technologies. However, these technologies may reveal the use of some medications, which may cause embarrassment to the passenger. Alarm-resolution techniques that allow for privacy may help to alleviate this concern.

If the trace-detection technologies for passenger screening can be implemented using a walk-through portal, then they are not expected to be any more inconvenient than current passenger screening technologies. However, if the technology requires a closed space for air collection, passengers may resist due both to the discomfort of being in an enclosed space and to the perception of added delay.

Nonimaging Electromagnetic Technologies

As discussed in earlier chapters, improvements in current passenger screening devices are not expected to change the passenger-system interface appreciably. Technologies designed to locate and identify specific threat objects, rather than a variety of objects that trigger the alarms of present-day systems, will result in increased privacy and added convenience for the passenger.

Nonimaging microwave technologies are likely to raise concerns about using microwave radiation to detect threat objects. As with the imaging technologies, this issue is more about risk perception than actual risk, and approaches to allaying passenger concerns about the use of radiation for imaging technologies would be appropriate for the dielectric portals.

SUMMARY

Four categories of issues seem most relevant to public acceptance of passenger screening technologies: health, privacy, convenience, and comfort. Health concerns are more of

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a risk perception problem because the technologies under consideration do not pose significant health hazards. The analysis of the panel and the results of the workshop indicate that the problem may be dealt with effectively through good communications and public education efforts. Privacy concerns about displaying images of bodies and initiating physical contact may prove to be significant hurdles to implementation. Several procedural steps are available to help alleviate these concerns. Convenience in the form of

avoiding time delays appears to be a highly important factor in public acceptance, as well as in the overall successful functioning of the system. Technologies that take more than six seconds to screen each person are likely to encounter significant public resistance. It will be important to assess public reaction to, and acceptance of, the screening technologies. Methodological problems, which are inherent in carrying out such assessments, need to be taken into consideration to avoid obtaining invalid results.