ABSTRACT
Designed entities must effectively communicate necessary information to the user, regardless of ambient conditions or the user’s sensory abilities [1].
A traveler using her cell phone in the airport has trouble hearing her caller because of the loud ambient background noise in the terminal. Much of accessible design deals with perceptual issues, overcoming ambient noise, or providing adequate tactile feedback. Emergency warning systems are prime examples of systems that must be perceptible by as many people as possible. To overcome unknown and unpredictable ambient conditions, the sounds are loud, employing an attention-getting pitch alternating in intensity or pitch. The lights are bright, vivid, and most often flashing.
