ACRP Research Report 175: Improving Intelligibility of Airport Terminal Public Address Systems provides design guidelines to improve public address speech intelligibility for passenger-processing interfaces for all types and sizes of airport terminal environments. These guidelines are intended to be used by airport operators and design consultants.
The guidelines include (1) a summary of data on public address systems, terminal finishes (e.g., walls, floors and ceilings) and background noise levels in a variety of airport terminals, (2) identification of acoustical shortcomings and the results of impacts on existing public address systems; and options for enhancing intelligibility in existing airport terminals as well as ensuring intelligibility in new terminal designs.
Audible announcements in airport terminals are often hard to understand. Given that the airport terminal environment is dynamic, the speech intelligibility of public address systems can decline and people can find it hard to understand announcements due to background noise and/or poor system design. Understanding announcements is even harder for (1) hearing-impaired travelers, (2) people for whom English is not their native language, and (3) distracted travelers. Poor intelligibility in public address systems degrades the efficacy of fire alarm notifications and other public service and emergency announcements that are critical in airport terminals.
The report reflects empirical research on existing acoustical conditions in airport terminals and demonstrates how terminal architecture and the design of public address systems within terminals affect intelligibility of announcements.
Under ACRP Project 07-14, research was conducted by a team of specialists lead by Wilson Ihrig. The design guidelines were developed through field measurements at airports as well as an online questionnaire to collect information from the airport industry (airlines, airports, and consultants) to review how the industry understands factors related to speech intelligibility. A passenger survey was also developed to gain insight on ways airports can conduct their own research on human factors specific to their airports.