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Improving Intelligibility of Airport Terminal Public Address Systems (2017)

Chapter: Chapter 5 - Human Factors Affecting PA System Intelligibility

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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
×
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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Suggested Citation:"Chapter 5 - Human Factors Affecting PA System Intelligibility." National Academies of Sciences, Engineering, and Medicine. 2017. Improving Intelligibility of Airport Terminal Public Address Systems. Washington, DC: The National Academies Press. doi: 10.17226/24839.
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40 5.1 Introduction Although the PA system design and acoustical environment may be optimally designed, the human factor ultimately determines whether a PA announcement is heard, understood, and acted on. This chapter considers what human factors may influence attention, perception, and effective listening to PA announcements. Effective listening is assumed here to be where the passenger has heard, understood, and can act on the information given in a public announcement message. Beyond speech intelligibility, which requires that the message has been heard and (nominally) understood, effective listening carries with it the element of the human factor. 5.2 Psychology of PA Announcement Intelligibility: Attention and Perception This section discusses attention and perception and how they affect whether people will hear and understand PA announcements. Research shows that auditory attention can be conducted in two ways: “bottom-up” or “top- down” processing. • Bottom-up processing begins with the stimulus, and the stimulus influences what listeners perceive. For example, listeners may start with no preconceived idea of what they are hearing and the stimulus itself influences their perception of what they are hearing. Bottom-up pro- cessing is stimulus-driven and the perception of the message itself directs the listeners’ cogni- tive awareness of what they are hearing. In PA terms, the message content influences what the listener perceives of the message. • Top-down processing uses the listeners’ personal experiences and knowledge, individual expectations, and current goals to influence perception. With top-down processing, listeners use what they know in order to perceive what they are attending to. Top-down processing is also goal driven, which can be either voluntary or task-dependent. In PA terms, the listeners themselves influence how they process and understand the message. From a theoretical perspective in an airport environment: An experienced passenger is likely to be using top-down processing to actively seek information from auditory messages and will have expectations regarding the information and format of those messages based on past experiences. It can be assumed that the experienced passenger would be an effective listener, actively seeking the information from the message and able to perceive, through past experience, what is required from them and to act accordingly. Frequent passengers employing top-down processing would know what they are searching for and employ a template-based search (Fritz et al. 1994). However, simple real-world observations from a passenger pilot study suggest that, contrary to the theory that experienced passengers will be more active listeners, these passengers actually tend Human Factors Affecting PA System Intelligibility C h a p t e r 5

human Factors affecting pa System Intelligibility 41 to “tune out” the PA messages—for example, frequently using headphones to isolate themselves from exterior messages. This behavior changed in the gate area, where they actively listened for information directly relevant to their journeys—for example, listening for when their allocated seat row or boarding group could board the plane. This suggests that they were only actively listening at points in their journeys when they knew information would be provided about actions they needed to take—particularly information that might not be available through other channels. (A high pro- portion of business passengers interviewed in the airport passenger survey noted that they looked for updates and flight details on their mobile devices using airline apps and texts; these would offer information about gate numbers, delays, etc., but would not give boarding instructions.) Let’s return to the theory of bottom-up information processing and apply it to an airport environment: A novice, infrequent or inexperienced passenger is likely to process information in a bottom-up way. In- experienced passengers having no expectation of the flight information messages would employ bottom- up processing, seeking information from the PA message and identifying salient points in the message in order to understand it. The processing of the salient points could almost be considered as highlighting certain features in comparison to their neighbors, for example destination names, times, etc. which stand out as salient within a message. The research suggests that novice passengers may not be actively listening and so will be more likely to employ bottom-up processing (Fritz et al. 1994). Real-world observations from the pilot study support the theory that inexperienced passengers are not actively listening at all points in their journey through the airport. Inexperienced passen- gers stated that they were often distracted by other activities in shops and food outlets and so were unlikely to be paying attention to PA announcements. However, at key points in their journeys, they actively sought information—such as immediately after leaving the security screening area and in the departure hall or gate areas as their departure time neared. Because of the multiple auditory and visual stimuli encountered in an airport, the inexperienced passenger was no more likely than the experienced passenger to be actively listening for PA messages. Use key words such as flight destinations as salient points at the beginning of the announcement to draw passenger attention to PA messages. An important concept in processing information is the notion of passengers being “primed” to listen for a message. Research in attention and perception suggests that even relaxed partici- pants who are not considered to be actively listening, but are pre-primed with the expectation of a message, will on some level be “ready to attend” to the message (Cherry 1953). Prepriming may be helpful in getting passengers to be more attentive to PA messages. For example, if check-in agents were to regularly instruct passengers to “listen for PA messages,” this could increase the priming effect. (This instruction could also be incorporated into self-service check-in machines as a closing message on the screen.) A version of priming can also be achieved by repeating PA messages (Labiale 1990). The first PA message serves as a primer to attract attention to the message, and a repeat of the message immediately or shortly after allows passengers to process the information. It is best to play the messages consecutively within a short space of time, as repeating a message after a long delay may result in passengers missing the content of the message a second time. Play or announce important messages twice consecutively to ensure that nonattentive listeners can focus on the PA message and then process the information presented within it. 5.2.1 Passenger Attention/Distraction Human attention is limited. It is impossible for us to attend to the multitude of stimuli assail- ing our senses on a minute-by-minute basis and so our brain is continually making decisions at a subconscious level as to which stimuli to attend to and which to disregard. The “subconscious” is the part of the mind that one is not fully aware of at a given moment but that is influencing one’s

42 Improving Intelligibility of airport terminal public address Systems feelings and actions in that moment. The subconscious awareness of messages is completely separate from a conscious decision made by a passenger concerning which messages to “choose” to pay attention to. Thus, our subconscious is processing data that our sensory receptors are constantly collecting about visual, auditory, and haptic stimuli. (Haptic stimuli are any form of stimulation involving touch.) The literature provides many studies to support the limited attention of humans, suggesting that we have a limited processing pool and that we, therefore, tend to focus our attention on one area to the exclusion of attention to another (Spence and Santangelo 2010). This is known as “selective attention” and is found to be especially evident when a person is presented with a competing task; for example, when someone is focusing on checking in, he or she cannot focus on announcements being made. With regard to airport messages, several competing stimuli may cause messages to be missed in such a complex environment. Passengers are notably less aware of auditory messages in areas like ticketing or check-in. Passengers focusing on checking in may subconsciously tune out other stimuli to deal with the task at hand. In the pilot study, when passengers were surveyed at a busy airport check-in area, they were often found to be genuinely unaware that any PA messages had been played in the preceding 10 minutes. Passengers also choose not to listen to announcements, or “tune them out.” Passengers may tune out messages for multiple reasons—they may be chatting, concentrating on work, shopping, eating or drinking, or reading. In general, passengers tune out when they believe that they do not require any information or when they believe that they have access to adequate information via other chan- nels (e.g., an airline app on a smartphone). Passengers are less likely to tune out in the gate areas; in the pilot study, passengers were noted to be more actively listening for when to board—information that they would be unable to access via their personal technology or on FIDS. Research also suggests how to increase the strength of the message when there are competing stimuli in the environment by making information directly relevant to the task required and removing messages that are not directly required, or relevant, to that area (Cherry 1953). For example, while at the check-in counter, passengers fail to hear security messages and often tune out messages they perceive to be relevant to other parts of the airport but not to them. Although it is understood that some PA messages are mandatory, general guidance would be to remove messages that are not directly relevant to a given airport location and to tailor relevant messages to the tasks required of passengers in that location. 5.2.2 Barriers to Attention and Perception Some psychological factors can be barriers to effective listening—stress and anxiety may be associated with the airport experience and an impending flight, or they may be stresses and anxieties particular to an individual, the individual’s previous experience of the airport, and/or his or her own personality. Stress and Arousal Psychological research tells us that stress and increased arousal hinder the amount of auditory information that can be processed. The greater the level of stress or arousal, the more limited the attentional resources there are to focus on other things (Ericksen and St. James 1986). It is difficult to predict the factor by which the level of attention to auditory features reduces under stress, because levels of stress and an individual’s reaction to stress are subjective. Stress in the airport environment may be especially acute, with evidence showing that the environment can induce depression, extreme anxiety, or panic attacks in vulnerable individuals (Bor 2007). Stress may be experienced by an individual for various reasons: time pressure, fear of flying, discomfort in crowds, and business or personal pressures related to the trip or not related

human Factors affecting pa System Intelligibility 43 to the trip. Cultural background, gender, age, and language skills may mediate how passengers deal with stress during traveling. Regardless of the reasons, the effect of stress on attention is the same—a narrowing of focus and reduced attentiveness to external stimuli such as auditory PA announcements. Thus, stress may be a strong determining factor in how well messages are attended to. Levels of stress experienced can vary by individual. For example, for a passenger who is anxious about flying, levels of stress may be high on check-in, drop a little after security on reaching the gate hold area where atten- tion may be diverted by nearby food and shopping, and then rise again when boarding begins. In another example, a bereaved passenger flying to a family funeral may have a constant level of stress throughout the journey through the airport. At key points in the passenger journey (where PA announcements include instructions requiring action or a response from the passenger), con- cise, simple, targeted messages are needed to capture potentially limited passenger attention. To draw attention and enhance message understanding • Keep messages simple • Use a “hook” or key word to draw attention • Use key words such as a flight destination, rather than a flight number, to draw attention Bias and Expectation Confirmation bias is a strong psychological phenomenon that may lead to a passenger mis- interpreting an auditory message (Fritz et al. 1994). Once an individual has formed a theory, hypothesis, or idea based on experience, research suggests it will take more than a single instance of contradicting information for that individual to alter his or her opinion. Our biases are stron- ger than our understanding of processes. Numerous studies in psychology illustrate that people (1) fail to attend to information that contradicts their expectations or (2) actively disregard contradictory information. Confirmation bias may be an issue, for example, for the regular traveler who is used to consis- tently using the same gate for a particular flight. Because of this bias, the traveler may fail to prop- erly attend to an auditory message when it is presented (for example, if the traveler is expecting to hear “Gate 6” when the announcement to proceed to the gate is called, he or she may assume the announcement said “6” when it did not). If presented with two conflicting pieces of information, a passenger may revert to the information that he or she feels most comfortable with, for example, the original information they received face to face from the check-in agent. Information given face to face is generally given greater precedence over information given by other means, such as PA announcements. Encourage check-in agents to urge passengers to listen for auditory messages in case of changes. Where messages provide information that represents a change to previously provided or expected information (e.g., a gate change), this fact should be clearly stated and be reiterated across other channels such as the FIDS. For example, it would be useful to have the FIDS screens display text information that is aligned with the updates presented in the auditory messages. Research suggests that, if important auditory messages are repeated consecutively, with only a short break between messages, passengers can focus attention on the message on its first play and process the information it provides on the second play. This allows time for individu- als to focus, recognize the information, reconcile that information with their understanding, and process the information to understand what action is required. This is also particularly useful for non-native listeners who require a longer time to process auditory information that is not in their native language (Zhang et al. 2005). Play important messages twice consecutively to allow passengers to hear, process, and act on information that they have been given. Clearly state if information presented is a change to information previously given (e.g., a gate change).

44 Improving Intelligibility of airport terminal public address Systems Limited Attention Research suggests that the passenger’s level of attention always affects whether announce- ments are processed and acted on or not. For example, a passenger with a long transfer time or a delay may simply “switch off” and fail to process any auditory messages (Umera-Okeke 2008). The passenger’s motivation to listen to a message strongly affects how much of a mes- sage is attended to and/or processed. The length of time a transfer passenger may have to wait can affect attention span. A passenger with a long transfer time may assume that auditory messages are not immediately relevant and may tune out. A parallel example in a work envi- ronment would be a light workload, leading to lapses in attention; in the airport environment, long periods of waiting with little to do can lead a passenger to daydream, exhibit low levels of attention, or be diverted by other things (e.g., a tablet, computer, or personal music device) with the resulting likelihood that the passenger will miss announcements (Mense, Debney and Druce 2006). This tendency to switch off also applies to passengers with limited processing ability, although research suggests that someone with limited processing ability is particularly susceptible to the “cocktail party effect” and so will be more receptive to a message that contains his or her name in it (Cherry 1953). Although a message using a passenger’s name is useful where there is a need to directly address a particular passenger, this is not feasible for general flight announcements. Simple messages requiring little in the way of processing are preferable. To summarize, for some passengers, PA announcements are not as effective as a message delivery service, no matter how the message is manipulated. Thus, PA announcements should not be considered as a single source of information and should always be used in conjunction with other information sources, such as FIDS. Task Interference Passengers are often distracted from hearing announcements by tasks they are engaged in, such as conversations, ordering food and drinks, or interacting with their phones or tablets. However, passengers may choose to receive updates on their smartphones and so may have less need to hear announcements. 5.3 Message Content of Announcements Messages should be kept short, concise, and to the point (Miller 1956). Research and observations suggest that including an introductory preamble, for example, “Flying Airways welcomes you to Terminal 6 today and would like to . . .” may result in passengers “tuning out” a message before the core information has even been delivered. Keep conversational, chatty PA messages to a minimum. 5.3.1 Relevance Passengers’ attention can be drawn to a message by information that is directly relevant to them, even when they are not paying attention to announcements in general. The most effective way to draw attention is the passenger’s name (Cherry 1953). Airports already make calls for passengers to go to gates using specific passenger names when a flight is closing and those passengers are still expected at the gate. In this instance, the name should be used first to attract attention, and then the name should be repeated; the whole message should be simple, directly and immediately relevant, concise, to the point, and without introduction. Figure 5-1 illustrates this approach.

human Factors affecting pa System Intelligibility 45 5.3.2 Repetition Repeat key identifying information within a single message. Although passengers’ attention may be drawn by initial recognition of a key name or phrase, travellers may not immediately process or understand the initial stimulus that has drawn their attention. The ability to pro- cess message information varies widely across the general population and even across passenger types—frequent travelers will be more attuned to relevant messages and process information quickly, while novice travelers may require more time to process messages. Because passengers’ attention varies, repetition of the key identifying information (passenger name in the case of specific passenger information or flight destination) is advised so as to reach most passengers. This key identifying information can be used to focus on task- or location-relevant messages by using specific “hook” words to capture attention. With a good understanding of what captures people’s attention, it is possible to create audi- tory messages that will capture even the attention of people primarily focused on visual infor- mation. For example, passengers reading a FID board can still have their attention drawn to an auditory announcement by the right key word or phrase. The key words and the relevance of the message are particularly important here (Iwamiya et al. 2004). It is not sufficient to simply remove sensory clutter such as background music or to use other sound-reducing techniques in the environment; the message must capture the passenger’s attention. Higher level information such as flight destinations is particularly salient for the passenger and makes for very effective key words for gaining passenger attention. Passengers approached during the pilot study were readily able to state their destination but frequently had to refer to their tickets or documentation when asked their flight numbers. It is also logical to assume that, for the average traveler, a destination is easier to remember than a seemingly random collection of numbers and letters. Flight destinations are ideal key words that can be used to get passenger attention, for example: “Denver, Denver, Flight XY123 to Denver, now boarding at Gate 4.” 5.3.3 Message Content: Types of Speech Conversational vs. Clear Speech, Synthesized vs. Natural Speech Conversational speech is much harder to process and understand because there are no breaks between words. The breaks that we believe we hear between words are actually imposed by our perceptual system. Conversational speech, if written as it were spoken, would have no spaces between words and they would literally run into each other (as in “Rowsonetotenboardingnow”). Figure 5-1. Guidance for message format.

46 Improving Intelligibility of airport terminal public address Systems In fact, if a word were extracted from a sentence of conversational speech, it might not be as easily recognized as it would be when heard in isolation. PA announcements given in the gate areas are frequently rushed and presented in a con- versational rather than a “clear speech” style, making differentiation among words difficult (Payton, Uchanski and Braida 1994). In the presentation style called “clear speech,” the speaker speaks each word individually, verbally highlighting the spaces between the words using hard consonant sounds at the ends of words. Because meaningful, grammatically correct, and clearly spoken (as opposed to conversational style) sentences are better understood across a wider audience, providing training in this type of speech presentation to those staff making announcements in the gate areas would be especially helpful. Clear speech is consistent with the principles of universal design. The benefits of using clear speech have also been shown to increase as noise levels increase. Relative to live voice or recorded voice announcements (natural voice), synthesized voice requires additional time for comprehension as listeners adjust to the synthesized voice; thus, for a given message, the comprehension and speech intelligibility of a text-to-speech (TTS) announce- ment is reduced compared to natural voice (Tsimhoni, Green and Lai 2001, Venkatagiri 2003). Studies suggest that the following techniques are useful: • Using a slightly higher TTS signal level compared to natural voice announcements. • Repeating the important TTS message to allow passengers to adjust to the synthesized voice. • Minimizing use of TTS messages in areas where conditions challenging to speech intel- ligibility are present (e.g., highly reverberant space and/or high percentage of non-native language listeners). 5.3.4 Message Content: Non-native Language Listeners Non-native listeners find clearly spoken sentence style easier to understand than conversa- tional style because they can identify individual words (Zhang et al. 2005). Familiarity with the semantic structure of the words in an announcement helps in recall and processing of the auditory message. This is particularly relevant for passengers who are from other countries and so may particularly benefit from hearing key words relevant to the flight information in a language familiar to them. For example, using the destination name as the key word, if you were playing a flight announcement for Rome, Italy, you would make an additional flight announcement using the Italian names, “Roma, Italia.” Where it is relevant to reach a high proportion of non-native listeners, key words in the language of the flight destination or carrier are particularly useful. PA announcements in gate areas are often spoken quickly, making it particularly difficult for non-native listeners to understand. Repeating a message after a very short delay allows time for non-native listeners to process what they are hearing and understand its meaning. The delay must be brief: if the delay between the original and the repeated message is too long, passengers may have returned to conversations, phones, tablets, or other distractions and fail to catch the entire message again. The first message is to draw the passenger’s attention, while the second message gives the passenger time to process and understand the information. 5.4 Message Delivery: Gender Early human factors research into male versus female voices when attempting to command listeners’ attention was related to aircraft warning systems and was specific to aircrew. This research found that the female voice was more authoritative and better at getting aircrew to do

human Factors affecting pa System Intelligibility 47 what they needed to do, and so, although male voices are now sometimes used for systems such as ground proximity warnings and traffic collision avoidance, female voices dominate the realm of aircraft warning systems. The early studies documented greater physical response markers (such as heart rate) to messages spoken by females than males and a faster response rate to instructions. More recent research also suggests that female speakers are more intelligible than male speakers (Amano-Kusumoto and Hosom 2011, Alm and Behne 2015). In some contexts, male speakers may be just as clear and effective as female speakers; also, male speakers may be more effective for certain listeners because those listeners prefer listen- ing to a male voice. Satellite navigation systems, for example, offer a choice of male and female voices to cater to personal preferences. However, research overall indicates that the female voice is more intelligible than the male voice for audio messages. This may be because female speakers tend to have larger vowel spac- ing and more precise timing and spaces between words and sentences. Although attentiveness to an announcer’s voice may be influenced by personal preferences, studies show that where intelligibility is an issue—such as where there is a high proportion of non-native speakers—a female voice is preferable. Diction and timing are important considerations for all speakers making announcements; the female voice can provide better intelligibility for audio messages and can be more effica- cious for specific types of announcements (e.g., announcements in the international terminal and text-to-speech announcements). Background Noise and Auditory Clutter TVs are often in food court and gate areas (see Figure 5-2). TV audio volumes are often set to a relatively low level so that the volume does not carry too far from the immediate areas they are sited in. However, these sources of additional auditory output are not linked to the PA system and so will continue to play during PA announcements. For some passengers, this source of noise may be a distraction or may interfere with the audibility of the announcements and cause the passengers to have difficulty hearing targeted auditory messages (Potter and Choi 2006). If it is not possible for this competing auditory channel to be linked to the PA system and paused during airport announcements, then it is important to ensure that the volume and clarity of the PA system in these areas can override such competing auditory streams. Background music is also sometimes played in food court areas; if the music and announce- ments are broadcast over the same loudspeaker system, it is helpful to pause the music before PA Figure 5-2. Cafe environment where auditory clutter, such as background music or TV may be present. Photo Credit: CCD

48 Improving Intelligibility of airport terminal public address Systems announcements so that the announcements can be heard, processed, and understood. However, if both systems use different loudspeakers, then it may be difficult to integrate the two systems. Reduce all unnecessary background noise. Where possible, ensure that all electronic sources of background sound are paused when a PA announcement is played so that the back- ground sounds do not compete with the auditory message. Gate Areas and Auditory Clutter Gate areas can become busy at the beginning of a flight’s boarding process immediately prior to a flight’s departure. Some passengers (often business travelers) tend to stand and wait in the gate area entrance nearest to the desk and the boarding entrance. In this location, on the bound- ary between the gate area and the adjacent corridor, gate area announcements are often muffled and sometimes difficult to hear. Frequently, gate announcements from adjacent gates clash or overlap, making both announcements difficult to hear and understand. Gate agents are often focused on getting the flights that they are responsible for boarded and may not be aware that an adjacent gate’s agent is already mid-announcement. This often leads to announcements at adjacent gates being made in parallel (overlapping); consequently, there is poor clarity of indi- vidual messages within the gate area, which makes it difficult for passengers to distinguish the content of the message that is relevant to them. Gate agents should ensure that their messages are played or spoken in isolation and that messages do not overlap with neighboring gate PA messages. Gate areas often have the greatest variations in clarity of message because announcements are frequently made by individual gate staff, rather than being prerecorded, standardized announce- ments. Passengers frequently say that PA announcements in these areas are muffled, are not spoken clearly enough, or are spoken too quickly. The gate agent may be on the tenth flight of the shift and so be inclined to run through a repeated announcement quickly; however, gate agents should be prompted to remember that, for passengers seeking information about an imminent departure, each announcement is an important announcement. PA announcements should be spoken clearly and at a measured pace. 5.5 Message Cuing Cuing and the “Absence” of Background Noise Passenger attention can also be drawn by the sudden absence of stimuli if there recently was stimuli (Cherry 1953). For example, if an airport plays background music, a break in the music will cue an announcement. Although a passenger may be paying explicit attention to reading the information on a display board, a passenger cannot completely exclude auditory input, suggest- ing that, at some level, the passenger’s mind is attending to it implicitly. Breaks in background noise should immediately precede an auditory message and be short enough for passengers to notice the absence of such noise and draw their attention to the auditory output and without being so long that the passenger’s attention is again lost. Cuing Tones Limited research in the field of complex auditory perception makes it difficult to categorically define how complex sounds—such as conversational speech—are affected by preceding and following sounds. Studies are frequently conducted in locations that are not representative of the complex environments presented by airports and often test single tones in isolation without background noise (Lotto and Holt 2011). In the absence of direct, real-world research, the fol- lowing guidance is provided. This guidance can be applied to any complex environment so as to have the greatest chance of gaining listener attention.

human Factors affecting pa System Intelligibility 49 Where cuing tones are used • Use short familiar tones • Associate tones to specific types of announcements • For gate areas in close proximity, do not overlap messages—especially not messages with tones • Precede all emergency messages with a meaningful alarm sound or tone • Combine alarms/tones with voice instructions 5.6 Passenger Journey Maps and Passenger Information Needs A passenger journey map is used to describe a passenger’s experience of traveling through an airport (journey), with key locations in the journey identified as touchpoints. For each touch- point, the passenger’s activities, thoughts, and interaction with the airport are analyzed. These passenger journey maps cover the following: • Passenger goals—what the passenger needs to accomplish at that stage of the journey • Passenger perspectives—insights into passenger thoughts and emotions • Airport information sources—the different information sources (e.g., PA, FIDS, and signs) the passenger uses to inform journey decisions • Passenger attention to PA announcements—the likely level of attention the passenger is giving to PA announcements at that point of the journey and potential influences on their attention • Insights—observations and insights into the passenger journey and aspects of the journey that can affect a passenger’s likelihood of hearing and understanding PA announcements To offer some context and passenger-specific detail, passenger journey maps have been devel- oped for three different passenger personas: • The family—parent(s) traveling with children, who typically fly together once or twice a year to go on vacation. The parents are reasonably confident flyers but may be traveling through an airport they have never been to before. They have particular needs, require- ments, and distractions because they are traveling with young children. See Figure 5-3. • The high-tech business traveler—a frequent traveler who takes multiple flights each month and is experienced in traveling through airports and in the requirements of the processes. The high-tech business traveler uses airline/airport apps to stay informed when traveling. See Figure 5-4. • The elderly infrequent traveler—has traveled through airports before, but does not travel frequently (once every few years). The elderly infrequent traveler’s recollection of the air- port process and what needs to be done at each stage is not always clear, and the whole experience of air travel and crowds in an airport is at times overwhelming. See Figure 5-5. The personas and passenger journey maps have been informed by the literature review, the pilot passenger study at a major North American airport, and the observations of human factors experts. 5.7 The Experience of Passengers with Impairments in Hearing and Sight 5.7.1 Passengers who Have Hearing Impairments and/or Are Older Passengers who have hearing impairments and older passengers (who may or may not have hearing impairments) benefit from implementation of all the previously noted guidance: keep it simple, use key word hooks to draw attention, and highlight pertinent information. People

Figure 5-3. User journey map—family. CURBSIDE PASSENGER GOALS AIRPORT INFORMATION SOURCES PA system Staff verbal communications Flight information display Customer service kiosk Signs Phone-airline app/text HIGH MEDIUM LOW PASSENGER PERSPECTIVE PASSENGER ATTENTION TO PA ANNOUNCEMENTS INSIGHTS • Find correct terminal and entrance. • Passenger focuses on ensuring that in the right place. • Follow security procedure • Passenger focuses on security process and listening to staff instructions. • Travel to gate • Passenger focuses on getting to gate. Will listen to announcements if they draw attention. • Find check-in desk • Check in to flight • Drop off bags • Passenger focuses on finding flight info and where to check in • Use leisure facilities (eat/shop/relax/work) • Passenger checks FIDs for flight info then relax and entertain kids • As departure time draws closer attention rises. • Wait to be called to board • Board plane • Passenger is aware boarding is getting close and that announcements likely to be relevant to them. • Wait for bags to arrive • Collect bags • Passenger anxiously waits for bags and will be alert to messages. • Once baggage carousel announced passenger’s focus shifts to looking for bag on belt. SECURITY GATE CORRIDORTICKETING/ CHECK IN DEPARTURES HALL/ FOOD COURT GATE AREA BAGGAGE CLAIM USER JOURNEY MAP “Where do we go?” • Passenger engages in check in and verbal interaction with staff - Unlikely to be listening out for PA announcements. • Security presents a time of heightened arousal for passengers with focus on following staff instructions. • Numerous passenger distractions may lead to missed PA announcements. • Auditory clutter from TVs and music from shops and food and beverage outlets can mask PA announcements. • Message clash between adjacent gate rooms can make it difficult to understand PA announcements. • Large variability in vocal quality and clarity of gate announcements (local staff). Nonnative language listeners report some messages were hard to understand. “I wonder how long this line will take.” “Do we have to take our shoes off?” “What do I do with the push chair?” “How long do we have to walk for?” “I can’t wait to get home, I’m so tired.” “What belt is our bag coming on?” “Is our flight on time?” “Where do we check in?” “Where’s the toilet?” “How long have we got? Once I’ve checked the screen we can relax.” “Where can the kids eat?” “I need to listen for our boarding call.” “Will we board first with kids?” USER PERSONA: FAMILY

Figure 5-4. User journey map—high tech business traveler. CURBSIDE PASSENGER GOALS AIRPORT INFORMATION SOURCES PA system Staff v erbal communications Flight information display Customer service kiosk Signs Phone-airline app/text HIGH MEDIUM LOW PASSENGER PERSPECTIVE PASSENGER ATTENTION TO PA ANNOUNCEMENTS INSIGHTS • Find correct terminal and entrance. • Follow security procedure • Passenger focuses on the security process. • Travel to gate • Passenger focuses on transit to gate. • Find check-in desk • Check in to flight • Drop off bags • Passenger has already checked in online or uses self service kiosk. Minimal time spent in check in. • Use leisure facilities (eat/shop/relax/work) • Passenger focuses on phone/work/ music/talking with colleagues. • Wait to be called to board • Board plane • Passenger actively listens to boarding announcements as boarding information does not normally appear on other channels (e.g. airline apps) • Wait for bags to arrive • Collect bags SECURITY GATE CORRIDORTICKETING/ CHECK IN DEPARTURES HALL / FOOD COURT GATE AREA BAGGAGE CLAIM USER JOURNEY MAP “My taxi always drops me at the closest entrance.” • Message clash between adjacent gate areas can mak e messages difficult to understand. • Passengers do not expect to hear a PA announcement at check in. • Flight information PA announcements are not usually provided in security line as passengers cannot take action while in line. “I hope the lines are as small as last week.” “I travel regularly and know where my airline check in is without hesitation.” “I’ll go to my usual cafe and do some work.” “If there’s any change to my flight, I’ll see it on my phone.” “I need to listen out for when my row is boarding.” “I want to be first on the plane.” “I’ll call to check that my taxi is ready and waiting for me.” “I’ll grab a bottle of water en route to the gate.” USER PERSONA: BUSINESS TRAVELER • Passenger moves straight from taxi into the check in hall. • Passenger waits for bags and is alert for messages • Once baggage carousel announced passenger’s attention shifts to looking for bags. • Passengers in food outlets with background music may miss PA announcements. • The number of passengers using airline apps and text alerts is increasing. • Location-based apps and other digital channels are increasing in importance.

CURBSIDE PASSENGER GOALS AIRPORT INFORMATION SOURCES PA system Staff verbal communications Flight information display Customer service kiosk Signs Phone-airline app/text HIGH MEDIUM LOW PASSENGER PERSPECTIVE PASSENGER ATTENTION TO PA ANNOUNCEMENTS INSIGHTS • Find correct terminal and entrance. • Follow security procedure • Passenger focuses on security process. • Travel to gate • Passenger focuses on transit to gate. • Find check-in desk • Check in to flight • Drop off bags • Passenger focuses on finding the right check-in desk. • Use leisure facilities (eat/shop/relax/work) • Passengers may actively listen for PA announcements for reassurance. • Wait to be called to board • Board plane • Passenger may ask staff and sit actively listening. • Wait for bags to arrive • Collect bags SECURITY GATE CORRIDORTICKETING/ CHECK IN DEPARTURES HALL / FOOD COURT GATE AREA BAGGAGE CLAIM USER JOURNEY MAP “Where do I go?” • Messages clash from adjacent gate area can make messages difficult to hear and may cause confusion. • PA announcements should align with FIDs. • Elderly infrequent passengers actively listening to PA annoucements may be confused by retail messages, which are played at some airports. • Elderly infrequent travelers can be confused in noisy environments. • PA announcement at this point may add to confusion and cognitive load • Curbside is often a busy environment with traffic noise. Preferable to keep information (PA or other) clear and simple. • Elderly infrequent travelers would benefit from carousel allocation being announced via PA in addition to screen based notifications. “Will they tell me what I have to do?” “How long will it take to walk to the gate?” “What do I do?” “Which line should I join?” “Where are the comfy seats? “It’s so busy and noisy in here.” “All these messages are confusing.” “I hope our bags arrive.” USER PERSONA: ELDERLY INFREQUENT TRAVELER • Passenger focuses on ensuring that in the right place. • Passenger anxiously waiting for bags and will be alert to messages. • Once baggage carousel announced focus shifts to looking for bag. Figure 5-5. User journey map—elderly infrequent traveler.

human Factors affecting pa System Intelligibility 53 with hearing impairment also have challenges processing consonant sounds. Consonant inten- sity increases as part of clear speech and so clear speech could be seen to benefit older listeners (and listeners with hearing impairments) as well as improving general intelligibility for non- hearing-impaired listeners. Clear speech is consistent with the principles of universal design. The literature review notes that there is a lack of human factors and behavioral research into the use of induction loops and assistive devices in airports and public spaces. As such, general human factors guidance is presented, rather than specific research-backed findings. Where induction loops or other systems are installed to help passengers with hearing impair- ments, the airport must find ways to communicate the provision effectively and clearly to the passengers. Possible methods include • Informing passengers of the hearing loop provision in advance of their visit (e.g., via the website or booking service) and • Making passengers aware of the hearing loop provision on their arrival to the airport, so they can use it if they require it, and informing passengers where they can go to get assistance if needed. Passengers need to be aware of the zones or areas where the induction loops or other sys- tems are installed and where they are not installed, so that they can plan accordingly and not rely on the service in an area that has no hearing loop provision. When available, engage passengers having hearing impairments at every opportunity—at booking, at check-in, and through signage—to make them aware that a hearing loop is available. Unlike other assistive listening systems (such as FM or infrared), loop systems are easy to use, with hearing aids that use telecoils (T-coils). As of 1989, all hearing aids sold in the United States are equipped with T-coils (FCC 2015). These hearing aids are typically equipped with a switch (T or MT setting) that enables the T-coil to pick up PA announcements broadcast over a loop that can encircle a room. An increasing number of passengers use smartphone airline apps and text services that pro- vide them with personal flight-specific updates; these may affect hearing-impaired passengers’ uptake of use of hearing induction loop systems for flight announcements, and it is expected that some passengers with hearing impairments will forego using the hearing induction loop systems and instead rely on these apps/services. In light of this, airport planners must remain open to adapting to future technologies and to implementing the most usable and effective methods of ensuring that all passengers are made aware of announcements in a timely manner. 5.7.2 Passengers with Visual Impairments Passengers with visual impairments have a stronger need to recognize whether an auditory sig- nal is pertinent to them and to be able to understand any information given by that message. Some research has shown that such passengers find that many PA messages are too long and contain unnecessary information such as welcome greetings and polite expressions (Iwamiya, et al. 2004). The previous guidance on the need to draw attention to key information and keep the mes- sages short and to the point is even more relevant for passengers with visual impairments. Keep it simple—remove unnecessary greetings and polite expressions. 5.8 Interplay between Flight Information Displays and PA Announcements Passengers typically check their flight information on the flight information display sys- tems (FIDS) on arriving at check-in and then again once they’ve gone through security. They check whether the flight is on time and what gate it is departing from. Passengers observed and

54 Improving Intelligibility of airport terminal public address Systems interviewed in airports do not report seeking flight information from PA messages in the check-in area or in the security screening area. Once through security, an increasing number of passengers use smartphone apps and/or text updates from their airlines for flight information; these passengers state that they feel comfortable that they will be informed via these channels should there be any update, delay, or gate change. Passengers have been seen referring to the FIDS in the departure hall and gate areas; within these two areas, when passengers’ focus is on flight information, it is possible that their atten- tion could be drawn to PA announcements using destination- or name-specific “hooks.” It has also been observed that, on hearing a PA announcement that directly affects his or her flight, a passenger is likely to check the flight details on the nearest FIDS. Passengers actively seek information from PA announcements in the gate lounge and gate corridor areas when they are seeking information about when to board their flight, because their apps and the FIDS do not display this information. Given the many ways passengers can now receive information about the status of their flights, consistency of information across the different information channels, particularly FIDS and PA systems, is critically important to support passenger confidence and avoid confusion and undue stress. 5.9 Guidance The following guidance has been introduced and discussed in this chapter: 5.9.1 Attention and Perception and Message Content • Clearly state if information presented is a change to information previously given. • Keep messages simple and concise. • Speak announcements clearly and at a measured pace. • Play or announce important messages twice consecutively. • Minimize audio clutter. • Consider using a female voice for specific types of announcements where certain factors challenge listeners and reduce attention or intelligibility (e.g., international terminal, text-to-speech). • Present flight information—in particular, updates—consistently across PA announce- ments and FIDS to avoid conflicts and confusion. 5.9.2 Message Cuing • Precede each announcement with a notable break in background music to draw attention to and furnish a cue for the announcement. • Precede announcements with short, familiar tones, particularly for emergency messages. • Associate tones with specific types of announcements. • For gate areas in close proximity, do not overlap messages, especially messages with tones.

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TRB's Airport Cooperative Research Program (ACRP) Research Report 175: Improving Intelligibility of Airport Terminal Public Address Systems provides design guidelines to improve public address systems for all types and sizes of airport terminal environments. The guidelines include a summary of data on public address systems, terminal finishes and background noise levels in a variety of airport terminals, identification of acoustical shortcomings, and the results of impacts on existing public address systems. The report provides options for enhancing intelligibility in existing airport terminals as well as ensuring intelligibility in new terminal designs.

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