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Accessible Design of Consumer Products


Guidelines for the Design of Consumer Products to Increase Their Accessibility to People with Disabilities or Who Are Aging

Working Draft 1.7 -- 1992

Compiled for The AD HOC Industry-Consumer-Researcher Work Group of the Consumer Product Design Guidelines Project by Gregg C. Vanderheiden and Katherine R. Vanderheiden Support for the preparation and dissemination of this document has been provided by the National Institute of Disability and Rehabilitation Research (NIDRR), US Dept. of Education\ under grant #G00850036 and by the Assistive Devices Division, Consumer Electronics Group, Electronic Industries Association.

This document is being sent out specifically for comment and suggested revisions from industry, consumers and researchers. Please feel free to mark up, comment, improve or take exception to the document in any way you see fit and send your comments to us. All responses and comments can be kept in strict confidence, allowing you to comment freely as individuals or organizations with anonymity. Your input is important to this process. Send comments to

CONSUMER PRODUCTS GUIDELINES PROJECT
Trace R & D Center
2107 Engineering Centers Bldg.
1550 Engineering Dr.
University of Wisconsin - Madison
Madison, WI 53706
Attn: Gregg C. Vanderheiden Ph.D.

©1991 Copyright Board of Regents, University of Wisconsin System

NOTE: To facilitate this document's review and use, you are free to duplicate and disseminate it freely. You may also excerpt ideas and materials from it freely. However, please send us a copy of your work as well for our information and interest.

Some of the charts and concepts in this document are taken from other authors and publications. These are so marked, and separate permission must be sought directly from those authors or publications before use (apart from copying this whole document).

The opinions expressed in this document do not necessarily reflect the opinions of NIDRR, the Assistive Devices Division of EIA or the individuals listed as contributors. Nor do all of the opinions necessarily represent the opinion of the compilers, since this document represents a compendium of input from many sources.

ABOUT THE PROJECT WORK GROUP

The AD HOC Industry-Consumer-Researcher Work Group is an open group composed of those individuals interested in more accessible consumer product design and contributing to the development and refinement of these guidelines. The work group is headquartered at the Trace R & D Center at the University of Wisconsin - Madison. Anyone can join by reviewing, and submitting comments to correct, elaborate or extend these guidelines. Communications of the ad hoc work group are carried out by mail to facilitate participation by industry and consumer representatives who would not otherwise be able to attend particular meetings or conferences. To participate in the work group, simply send your comments, ideas, corrections or extensions to the guidelines to the address on the cover of this report.

ACKNOWLEDGEMENTS

Many individuals contributed to the development of these guidelines, both formally and informally, including students who participated in an Industrial Engineering Department Seminar on Design and Human Disability and Aging at the University of Wisconsin - Madison. Among the professionals, consumers, industry representatives and students contributing to these guidelines are:

Karen Athens
Keith Bednar
Jane Berliss
Lori Beth
Mary Ann Bird
Peter Borden
Eli Chu
Suruedee Chumroum
Raúl Colón
Cynthia Cress
Joanne Deda
Thomas Findley
Jackie Finley
Clint Gibler
Bob Glass
Sue Gmeinder
Paul John Grayson
Mickey Greenberg
Jackie Greshik
Debra A. Griffith
Andy Hesselbach
Ken Jelinek
One-Jang Jeng
Jeff Jentz
Andrea Johnson
Tim Jones
Dennis Jones
Tracy Kidd
Kimberly Kline
Fritz Klode
Jeff Kolff
Yueh-Chuan Kung
Dennis La Buda
Chris LaPorte
Charles Lee
David J. Lee
Seongil Lee
Patti Lindstrom
Fred Lupton
Robert Lynch
Diane Meyers
James Mueller
Young Lae Park
Lawrence Scadden
Joseph Schauer
Debbie Schlais
Lisa Schroeder-Omar
Debbie Sherman
Paul Sura
Jeff Tackes
Sidney Tang
Christine Thompson
Mike Thompson
Michelle S. Vandall
John Ward
Dawn Wadzinski
Steven Wiker
Greg Wierman
Marcy Worzala
Chien-Ling Yang
Thomas Yen
Dave Zehel

A special thanks to Christine J. Thompson, who assisted in the preparation of many of the graphics in this document.

ABOUT THE AUTHORS

The authors of this document are too numerous and diverse to easily identify and include the compilers, those listed in the acknowledgements, those cited in the text and an even greater number of individuals whose ideas have filtered down through the grapevine and are captured here. This document represents their ideas as compiled and extended by Gregg C.Vanderheiden and Katherine R. Vanderheiden.

Gregg Vanderheiden is an associate professor in the Industrial Engineering Department's Human Factors Program at the University of Wisconsin-Madison and Director of the Trace Research and Development Center at the University (a Rehabilitation Engineering Center focusing on access to communication, computer and electronic devices by people with disabilities). Dr. Vanderheiden has been active in the field of technology and disability for over 20 years, has published numerous papers, chapters and books and has been principal investigator on over 40 grants and contracts in the area.

Katherine Vanderheiden is an independent business and professional education consultant. She is a CPA with 10 years experience in industry, including public accounting, serving as a computer systems implementation coordinator for a large hospital and developing training courses and materials for internal and industry use in her capacity as Manager in the Education Consulting Division of Arthur Andersen & Co.


CONTENTS

PART I - Introduction

PART II - Disabilities and Specific Barriers to Accessibility

PART III - Guidelines for More Accessible Design

References and Resources

Appendix: Guidelines Checklist


GUIDELINES BY SECTION

SECTION 1 - OUTPUT / DISPLAYS

Maximize the number of people who can/will ...

O-1 ...hear auditory output clearly enough.
O-2 ...not miss important information if they can't hear.
O-3 ...have line of sight to visual output and can reach printed
O-4 ...see visual output clearly enough.
O-5 ...not miss important information if they can't see.
O-6 ...understand the output (visual, auditory, other)..
O-7 ...view the output display without triggering a seizure.

SECTION 2 - INPUT / CONTROLS

Maximize the number of people who can ...
I-1 ...reach the controls.
I-2 ...find the individual controls/keys if they can't see them.
I-3 ...read the labels on the controls/keys.
I-4 ...determine the status/setting of the controls if they can't see them.
I-5 ...physically operate controls and other input mechanisms.
I-6 ...understand how to operate controls and other input mechanisms.
I-7 ...connect special alternative input devices.

SECTION 3 - MANIPULATIONS

Maximize the number of people who can ...
M-1 ...physically insert and/or remove objects as required for operation.
M-2 ...physically handle and/or open the product.
M-3 ...remove, replace, or reposition often-used detachable parts.
M-4 ...understand how to carry out the manipulations necessary.

SECTION 4 - DOCUMENTATION

Maximize the number of people who can ...
D-1 ...access the documentation.
D-2 ...understand the documentation.

SECTION 5 - SAFETY

Maximize the number of people who can ...
S-1 ...perceive hazard warnings.
S-2 ...use the product without injury due to unperceived hazards.

PART I - Introduction

Background

Beginning in 1984, joint government/industry efforts have attempted to address the accessibility of standard computer hardware and software by people with disabilities. One of the major results of these efforts was the development of design guidelines for use by computer manufacturers and software developers . These guidelines were prepared at the request of the computer companies to assist them in better understanding accessibility problems in computer design and to identify commercially practical strategies for making their products more accessible. The guidelines were developed using a cooperative industry-consumer-researcher-government consortium in order to provide the best information from all angles. The resulting guidelines (titled: Considerations in the Design of Computers and Operating Systems to Increase Their Accessibility to People with Disabilities) have been used by most major computer manufacturers in their ongoing efforts to make their products more accessible and usable by people with various types and degrees of disability. The Considerations document is a working document, and as such is continually evolving and improving (the current version is 4.2).

Purpose of This Document

This document represents a similar cooperative effort to develop design guidelines for the design of "consumer products." For this document, consumer products are defined as appliances and other electronic and mechanical devices available to the mass market for use in the home, school, office, or for use by the general public in the community. The purpose of these guidelines is 1) to point out problems encountered by people with various disabilities in using standard consumer products, and 2) to propose design alternatives which will result in increased usability of standard products by people with disabilities.

As with the computer guidelines, this document is designed to be purely informational in nature, and has been developed at industry's request to facilitate product designers' efforts to make their products more accessible. It represents the compilation of information from many sources and, as a working document, is under continual revision. To that end, comments and suggested revisions are solicited from all readers, particularly from product designers.

What is Accessible Design?

"Accessible Design" is the term used for the process of extending mass market product design to include people who, because of personal characteristics or environmental conditions, find themselves on the low end of some dimension of performance (e.g., seeing, hearing, reaching, manipulating). Accessible Design is not (or should not be) separate from standard mass market design. Rather it is an extension or elaboration of general design principles to cover a wider range of human abilities/limitations than has traditionally been included in product design.

Thus Accessible Design is a subset of what is termed Universal Design. Where Universal Design covers the design of products for all people and encompasses all design principles, Accessible Design focuses on principles that extend the standard design process to those people with some type of performance limitation (the lower ability tail of Universal Design).

Accessible Design is a balancing act. To begin with, we must acknowledge that it is not possible to design everything so that it can be used by everyone. There will always be someone with a combination of severe physical, sensory and cognitive impairments who will not be able to use it. However, it is equally unreasonable to rely on the existence (or development) of special designs for each major product to accommodate each one of the immense variety of disabilities (and combinations of disabilities). This makes it necessary to look toward a combination of approaches for meeting the needs of people with disabilities, ranging from the incorporation of features into products that will make them directly usable ("from the box") by more people with disabilities to the inclusion of features that make them easier to modify for accessibility.

Four Ways to Make Products More Accessible

Four different approaches to making products more accessible are discussed in this section and reflected in the Guidelines. In any one product, it may be necessary to use one or a combination of these approaches to achieve the desired level of accessibility. These approaches, in order of desirability, are:

  1. Direct Accessibility
  2. Accessibility via Standard Options or Accessories (from the manufacturer)
  3. Compatibility with Third Party Assistive Devices
  4. Facilitation of Custom Modifications

1. Direct Accessibility:

2. Accessibility via Standard Options or Accessories (from the manufacturer):

3. Compatibility With Third Party Assistive Devices:

3a. Compatibility with Special Interfaces or Accessories

3b. Compatibility with General Purpose Assistive Devices

4. Facilitation of Custom Modifications:

The Best Approach

Of the four approaches to Accessible Design, the first type, direct accessibility "from the box," is the best where it is possible. It allows the greatest access to products by persons with disabilities at the lowest cost. It also allows them to access products in public places where they could not otherwise modify the products to meet their particular needs. It also removes the stigma of "special" aids or modifications. This is especially important for older users who do not want to be labeled "disabled" even though their abilities are weakening.

It should also be noted that most of us become temporarily "disabled" in a number of ways throughout our lives. Sometimes it is by accident, such as a broken arm or eye injury. Sometimes it is by circumstance, such as operating things in the dark where we can't see well, in loud environments (vacuuming or teenagers) where we can't hear well, with things in our arms where we can't reach well, when we're tired or on cold medication and can't think well, etc. Only those products which were designed to be more easily used directly "from the box" (#1 above) will be of use to us then. As mentioned above, more accessible designs are also usually easier to use by everyone all the time - but only if the ease of use is directly built in.


PART II - Disabilities and Specific Barriers to Accessibility

Prior to reviewing the Guidelines presented in Part III, the reader who is not familiar with the demographics, causes and effects of major types of disabilities would benefit greatly from reviewing this section. The Guidelines assume a basic familiarity with this information. In addition, it is likely that new advances in design are not anticipated by the Guidelines. In those cases, knowledge of the basic characteristics of various disabilities will enable manufacturers to anticipate the effect of major design changes on their products' accessibility

A significant portion of our population (over thirty million in the U.S.) has impairments which reduce their ability to effectively or safely use standard consumer products. These impairments may be acquired at birth or through accident or disease. Note that many impairments which result in disabilities are associated with aging. This is especially significant, as the population as a whole is growing older. Although there is a tremendous variety of specific causes, as well as combinations and severity of disabilities, we can most easily relate their basic impact to the use of consumer products by looking at four major categories of impairment. The four categories are:

In addition, we will discuss the special case of seizure disorders as well as some of the common situations of multiple impairments.

Visual Impairments

Visual impairment represents a continuum, from people with very poor vision, to people who can see light but no shapes, to people who have no perception of light at all. However, for general discussion it is useful to think of this population as representing two broad groups: those with low vision and those who are legally blind. There are an estimated 8.6 million people with visual impairments (3.4% of the U.S. population). In the elderly population the percentage of persons with visual impairments is very high.

A person is termed legally blind when their visual acuity (sharpness of vision) is 20/200 or worse after correction, or when their field of vision is less than 20 degrees in the best eye after correction. There are approximately 580,000 people in the U.S. who are legally blind.

Low vision includes problems (after correction) such as dimness of vision, haziness, film over the eye, foggy vision, extreme near- or farsightedness, distortion of vision, spots before the eyes, color distortions, visual field defects, tunnel vision, no peripheral vision, abnormal sensitivity to light or glare, and night blindness. There are approximately 1.8 million people in the U.S. with severe visual impairments who are not legally blind.

Many diseases causing severe visual impairments are common in those who are aging (glaucoma, cataracts, macular degeneration, and diabetic retinopathy). With current demographic trends toward a larger proportion of elderly, the incidence of visual impairments will certainly increase.

Functional Limitations Caused by Visual Impairments

Those who are legally blind may still retain some perception of shape and contrast or of light vs. dark (the ability to locate a light source), or they may be totally blind (having no awareness of environmental light).

Those with visual impairments have the most difficulty with visual displays and other visual output (e.g., hazard warnings). In addition, there are problems in utilizing controls where labelling or actual operation is dependent on vision (e.g., where eye-hand coordination is required, as with a computer "mouse"). Written operating instructions and other documentation may be unusable, and there can be difficulties in manipulation (e.g., insertion/placement, assembly).

Because many people with visual impairments still have some visual capability, many of them can read with the assistance of magnifiers, bright lighting and glare reducers. Many such people with low vision are helped immensely by use of larger lettering, sans-serif typefaces, and high contrast coloring.

Those with color blindness may have difficulty differentiating between certain color pairs. This generally doesn't pose much of a problem except in those instances when information is color coded or where color pairs are chosen which result in poor figure ground contrast.

Key coping strategies for people with more severe visual impairments include the use of braille and large raised lettering. Note, however, that braille is preferred by only 10% of blind people (normally those blind from early in life). Raised lettering must be large and is therefore better for indicating simple labels than for extensive text.

Hearing Impairments

Hearing impairment is one of the most prevalent chronic disabilities in the U.S. Approximately 22 million people in the U.S. (8.2%) have hearing impairments. Of those, 2.4 million have severe to profound impairments.

Hearing impairment means any degree and type of auditory disorder, while deafness means an extreme inability to discriminate conversational speech through the ear. Deaf people, then, are those who cannot use their hearing for communication. People with a lesser degree of hearing impairment are called hard of hearing. Usually, a person is considered deaf when sound must reach at least 90 decibels (5 to 10 times louder than normal speech) to be heard, and even amplified speech cannot be understood.

Hearing impairments can be found in all age groups, but loss of hearing acuity is part of the natural aging process. 23% of those aged 65 to 74 have hearing impairments, while almost 40% over age 75 have hearing impairments. The number of individuals with hearing impairments will increase with the increasing age of the population and the increase in the severity of noise exposure.

Hearing impairment may be sensorineural or conductive. Sensorineural hearing loss involves damage to the auditory pathways within the central nervous system, beginning with the cochlea and auditory nerve, and including the brain stem and cerebral cortex (this prevents or disrupts interpretation of the auditory signal). Conductive hearing loss is damage to the outer or middle ear which interferes with sound waves reaching the cochlea. Causes include heredity, infections, tumors, accidents and aging (presbycusis, or "old hearing").

Functional Limitations Caused by Hearing Impairments

The primary difficulty for individuals with hearing impairment in using standard products is receiving auditory information. This problem can be compensated for by presenting auditory information redundantly in visual and/or tactile form. If this is not feasible, an alternative solution to this problem would be to provide a mechanism, such as a jack, which would allow the user to connect alternative output devices. Increasing the volume range and lowering the frequency of products with high pitched auditory output would be helpful to some less severely impaired individuals. (Progressive hearing loss usually occurs in higher frequencies first.)

Although not prevalent yet, there is much talk of using voice input on commercial products in the future. This, too, will present a problem for many deaf individuals. While many have some residual speech, which they work to maintain, those who are deaf from birth or a very early age often are also nonspeaking or have speech that cannot be recognized using current voice input technology. Thus, alternatives to voice input will be necessary to these individuals to access products with voice input.

Familiar coping strategies for hearing impaired people include the use of hearing aids, sign language, lipreading and TDD's (telecommunication devices for the deaf). Some hearing aids are equipped with a "T-coil" as well, which provides direct inductive coupling with a second coil (such as in a telephone receiver) in order to reduce ambient noise. Some other commercial products could make use of this capability.

ASL (American Sign Language) is commonly used by people who are deaf. It should be noted, however, that this is a completely different language from English. Thus, deaf people who primarily use ASL may understand English only as a second language, and may therefore not be as proficient with English as native speakers.

Finally, telecommunication devices for the deaf (TDD's) are becoming more common in households and businesses as a means for deaf and hard of hearing people to communicate over the phone. TDD's have always used the Baudot code, but newer ones receive both Baudot and ASCII.

Physical Impairments

Functional Limitations Caused by Physical Impairments

Problems faced by individuals with physical impairments include poor muscle control, weakness and fatigue, difficulty walking, talking, seeing, speaking, sensing or grasping (due to pain or weakness), difficulty reaching things, and difficulty doing complex or compound manipulations (push and turn). Individuals with spinal cord injuries may be unable to use their limbs and may use "mouthsticks" for most manipulations. Twisting motions may be difficult or impossible for people with many types of physical disabilities (including cerebral palsy, spinal cord injury, arthritis, multiple sclerosis, muscular dystrophy, etc.).

Some individuals with severe physical disabilities may not be able to operate even well-designed products directly. These individuals usually must rely on assistive devices which take advantage of their specific abilities and on their ability to use these assistive devices with standard products. Commonly used assistive devices include mobility aids (e.g., crutches, wheelchairs), manipulation aids (e.g., prosthetics, orthotics, reachers) communication aids (e.g., single switch-based artificial voice), and computer/device interface aids (e.g., eyegaze-operated keyboard).

Nature and Causes of Physical Impairments

Neuromuscular impairments include:

Skeletal impairments include joint movement limitations (either mechanical or due to pain), small limbs,missing limbs, or abnormal trunk size.

Some major causes of these impairments are:

Arthritis. Arthritis is defined as pain in joints, usually reducing range of motion and causing weakness. Rheumatoid arthritis is a chronic syndrome. Osteoarthritis is a degenerative joint disease. 31.6 million people in the U.S. suffer from rheumatic disease. The incidence of all forms of arthritis is now estimated at 900,000 new cases per year.

Cerebral Palsy (CP). Cerebral palsy is defined as damage to the motor areas of the brain prior to brain maturity (most cases of CP occur before, during or shortly following birth). There are more than 750,000 in the U.S. with CP (children and adults), and 15,000 infants are born each year with CP. CP is a type of injury, not a disease (although it can be caused by a disease), and does not get worse over time; it is also not "curable." Some causes of cerebral palsy are high temperature, lack of oxygen, and injury to the head. The most common types are: (1) spastic, where the individual moves stiffly and with difficulty, (2) ataxic, characterized by a disturbed sense of balance and depth perception, and (3) athetoid, characterized by involuntary, uncontrolled motion. Most cases are combinations of the three types.

Spinal Cord Injury. Spinal cord injury can result in paralysis or paresis (weakening). The extent of paralysis/paresis and the parts of the body effected are determined by how high or low on the spine the damage occurs and the type of damage to the cord. Quadriplegia involves all four limbs and is caused by injury to the cervical (upper) region of the spine; paraplegia involves only the lower extremities and occurs where injury was below the level of the first thoracic vertebra (mid-lower back). There are 150,000 to 175,000 people with spinal cord injuries in the U.S., with projected annual increases of 7,000 - 8,000. 47% of spinal cord injuries result in paraplegia; 53% in quadriplegia. Car accidents are the most frequent cause (38%), followed by falls and jumps (16%) and gunshot wounds (13%).

Head Injury (cerebral trauma). The term "head injury" is used to describe a wide array of injuries, including concussion, brain stem injury, closed head injury, cerebral hemorrhage, depressed skull fracture, foreign object (e.g., bullet), anoxia, and post-operative infections. Like spinal cord injuries, head injury and also stroke often results in paralysis and paresis, but there can be a variety of other effects as well. Currently about one million Americans (1 in 250) suffer from effects of head injuries, and 400,000 - 600,000 people sustain a head injury each year. However, many of these are not permanently or severely disabled.

Stroke (cerebral vascular accident; CVA). The three main causes of stroke are: thrombosis (blood clot in a blood vessel blocks blood flow past that point), hemorrhage (resulting in bleeding into the brain tissue; associated with high blood pressure or rupture of an aneurism), and embolism (a large clot breaks off and blocks an artery). The response of brain tissue to injury is similar whether the injury results from direct trauma (as above) or from stroke. In either case, function in the area of the brain affected either stops altogether or is impaired.

Loss of Limbs or Digits (Amputation or Congenital). This may be due to trauma (e.g., explosions, mangling in a machine, severance, burns) or surgery (due to cancer, peripheral arterial disease, diabetes). Usually prosthetics are worn, although these do not result in full return of function. The National Center for Health Statistics of the U.S. Public Health Service estimated a prevalence of 311,000 amputees in 1970. An incidence of approximately 43,000 new amputations per year is estimated, of which 77% occur in males, and 90% involve the legs. 40% of amputations are above the knee, 50% are below the knee, and 10% are at the hip.

Parkinson's Disease. This is a progressive disease of older adults characterized by muscle rigidity, slowness of movements, and a unique type of tremor. There is no actual paralysis. The usual age of onset is 50 to 70, and the disease is relatively common - 187 cases per 100,000.

Multiple Sclerosis (MS). Multiple sclerosis is defined as a progressive disease of the central nervous system characterized by the destruction of the insulating material covering nerve fibers. The problems these individuals experience include poor muscle control, weakness and fatigue, difficulty walking, talking, seeing, sensing or grasping objects, and intolerance of heat. Onset is between the ages of 10 and 40. This is one of the most common neurological diseases, affecting as many as 500,000 people in the U.S. alone.

ALS (Lou Gehrig's Disease). ALS (Amyotrophic Lateral Sclerosis) is a fatal degenerative disease of the central nervous system characterized by slowly progressive paralysis of the voluntary muscles. The major symptom is progressive muscle weakness involving the limbs, trunk, breathing muscles, throat and tongue, leading to partial paralysis and severe speech difficulties. This is not a rare disease (5 cases per 100,000). It strikes mostly those between age 30 and 60, and men three times as often as women. Duration from onset to death is about 1 to 10 years (average 4 years).

Muscular Dystrophy (MD). Muscular dystrophy is a group of hereditary diseases causing progressive muscular weakness, loss of muscular control, contractions and difficulty in walking, breathing, reaching, and use of hands involving strength. About 4 cases in 100,000 are reported.

Cognitive/Language Impairments

Functional Limitations Caused by Cognitive/Language Impairments

The type of cognitive impairment can vary widely, from severe retardation to inability to remember, to the absence or impairment of specific cognitive functions (most particularly, language). Therefore, the types of functional limitations which can result also vary widely.

Cognitive impairments are varied, but may be categorized as memory, perception, problem-solving, and conceptualizing disabilities. Memory problems include difficulty getting information from short-term storage, long term and remote memory. This includes difficulty recognizing and retrieving information. Perception problems include difficulty taking in, attending to, and discriminating sensory information. Difficulties in problem solving include recognizing the problem, identifying, choosing and implementing solutions, and evaluation of outcome. Conceptual difficulties can include problems in sequencing, generalizing previously learned information, categorizing, cause and effect, abstract concepts, comprehension and skill development. Language impairments can cause difficulty in comprehension and/or expression of written and/or spoken language.

There are very few assistive devices for people with cognitive impairments. Simple cuing aids or memory aids are sometimes used. As a rule, these individuals benefit from use of simple displays, low language loading, use of patterns, simple, obvious sequences and cued sequences.

Types and Causes of Cognitive/Language Impairments

Mental Retardation. A person is considered mentally retarded if they have an IQ below 70 (average IQ is 100) and if they have difficulty functioning independently. An estimated 3% of Americans are mentally retarded. For most, the cause is unknown, although infections, Down Syndrome, premature birth, birth trauma, or lack of oxygen may all cause retardation. Those considered mildly retarded (80-85%) have an IQ between 55 and 69 and are considered educable, achieving 4th to 7th grade levels. They usually function well in the community and hold down semi-skilled and unskilled jobs. People with moderate retardation (10%) have an IQ between 40 and 54 and are trainable in educational skills and independence. They can learn to recognize symbols and simple words, achieving approximately a 2nd grade level. They often live in group homes and work in sheltered workshops. People with severe or profound retardation represent just 5-10% of this population.

Language and Learning Disabilities. Aphasia, an impairment in the ability to interpret or formulate language symbols as a result of brain damage, is frequently caused by left cerebral vascular accident (stroke) or head injury. Specific learning disabilities are chronic conditions of presumed neurological origin which selectively interfere with the development, integration, and/or demonstration of verbal and/or non-verbal abilities. Many people with learning disabilities are highly intelligent aside from their specific learning disability. 1-8% of school-aged children and youth have specific learning disabilities.

Age-Related Disease. Alzheimer's disease is a degenerative disease that leads to progressive intellectual decline, confusion and disorientation. Dementia is a brain disease that results in the progressive loss of mental functions, often beginning with memory, learning, attention and judgment deficits. The underlying cause is obstruction of blood flow to the brain. Some kinds of dementia are curable, while others are not.

Seizure Disorders

A number of injuries or conditions can result in seizure disorders. Epilepsy is a chronic neurological disorder. It is reported that approximately 1 person in 15 has a seizure of some sort during his life, and between .5% and 1.5% of the general population have chronic, recurring seizures. A seizure consists of an explosive discharge of nervous tissue, which often starts in one area of the brain and spreads through the circuits of the brain like an electrical storm. The seizure discharge activates the circuits in which it is involved and the function of these circuits will determine the clinical pattern of the seizure. Except at those times when this electrical storm is sweeping through it, the brain is working perfectly well in the person with epilepsy. Seizures can vary from momentary loss of attention to grand mal seizures which result in the severe loss of motor control and awareness. Seizures can be triggered in people with photosensitive epilepsy by rapidly flashing lights, particularly in the 10 to 25 Hz range.

Multiple Impairments

It is common to find that whatever caused a single type of impairment also caused others. This is particularly true where disease or trauma is severe, or in the case of impairments caused by aging.

Deaf-blindness is one commonly identified combination. Most of these individuals are neither profoundly deaf nor legally blind, but are both visual and hearing impaired to the extent that strategies for deafness or blindness alone won't work. People with developmental disabilities may have a combination of mental and physical impairments that result in substantial functional limitations in three or more areas of major life activity. Diabetes, which can cause blindness, also often causes loss of sensation in the fingers. This makes braille or raised lettering impossible to read. Cerebral palsy is often accompanied by visual impairments, by hearing and language disorders, or by cognitive impairments.


PART III - Guidelines for More Accessible Design

Structure and Organization of the Guidelines

In order to facilitate use by product design teams, this section is organized functionally rather than by disability area. Functional categories are as follows:

Output/Displays includes all means of presenting information to the user

Input/Controls includes keyboards and all other means of communicating to the product

Manipulations includes all actions that must be directly performed by a person in concert with the product or for routine maintenance; e.g., inserting disk, loading tape, changing ink cartridge

Documentation primarily operating instructions

Safety includes alarms and protection from harm

Each guideline is phrased as an objective, followed by a statement of the problem(s) faced by people with disabilities. The problem statement is accompanied by more specific examples. Next, "design options and ideas" are presented to provide some suggestions as to how the objective could be achieved. Readers are encouraged to think of other ideas. Finally, additional data and specific information, along with illustrations, are presented at the end of each guideline.

The guidelines are stated as generically as possible. Therefore, all, some or none of the design options and ideas presented may apply in the case of any specific product. The recommended approach is to implement those options which together go the longest way toward achieving the objective of the guideline for your product. It is understood that this is not an ideal world, so it may currently be too expensive to implement all those ideas which would best achieve the objective. It is also anticipated that there will be other ways of meeting accessibility objectives than those discussed here, and such discoveries are encouraged. We would like to hear of them so that they can be included in future releases of these Guidelines.

Designer's Dilemma: Availability and Meaningfulness of Numbers

In trying to make products more accessible, the question of numbers quickly arises. How large should lettering be? What size button is large enough? How much pressure is too much, or not enough? In trying to make designs more accessible there are two tough principles that one has to come to grips with early.

  1. You cannot make a product absolutely accessible. You can make it more accessible, but there will always be people who cannot use it.
  2. Therefore... There are no magic numbers. There are no numbers to tell you that you have gone far enough and nothing more will help anyone.

At first this is hard to accept. Everyone wants a number to design to. Occasionally minimal numbers for minimal required accessibility are set, but ...

The Problem with Diversity of Types and Degrees of Impairment

This latter point is the most important. A key problem in picking or setting a number is deciding who to leave out. The reason for discussing accessible design in the first place is that the standard design process currently only targets "most" of the people, and then stops. Some target number is established that is "good enough" to cover 80%, 90% or 95% of the people, and then developers end up designing to that number and stopping - even if they could just have easily gone a bit further. And it is that last phrase that is important. Since no product can be made completely accessible, a designer can't ever win completely. Tough to accept or deal with, but a fact of life. The secret, then, is to go as far as one can in making the design accessible. Setting a number as "good enough" for "most people with disabilities" and then designing to it just repeats the mistake that was made in the standard design process.

For example, to specify exactly how large lettering should be in order to be visible, you must first ask "visible to whom?" For any number you cite, there will be people who could see it if it were just a little bigger and others who would be unable to read it if you made it any smaller. There would also be some who could not see it no matter how large you made it. Thus, there is no number that will allow all people to read it. You always end up leaving some people off. The question then isn't "How large must lettering be to be accessible?" The proper question is "How large can this lettering be and still work for this product?" The decision to make it as large as practical will make the product accessible to a greater number of people. However, the decision as to the exact amount of enlargement that can be effectively used on the lettering for any given product is a decision that must be made as a part of the design process for that specific product.

Numbers Do Have their Place

This is not to say that numbers are not useful. They are essential to any design process. The numbers needed, however, are not "target" numbers or "this is now accessible" numbers, but rather numbers that a designer can use as milestones to see how changes in a design will affect users. Whenever data of this type exist or are identified they will be either included or cited in these Guidelines. An example of this is Figure O-7-a on the sensitivity of people with photosensitive epilepsy to different flicker frequencies. The chart does not give a magic frequency that would be safe (wouldn't trigger a seizure in anyone) under all conditions. It does, however, clearly indicate that avoiding 20 hz flicker by as much as practical will clearly be to the benefit of those with photosensitive epilepsy.

Occasionally, recommended "minimum" or "maximum" values do exist. Sometimes they are created as part of regulations or standards which set a baseline that everyone must comply with for some product or market. In other cases, "rule of thumb" values exist which are known or believed to cover the majority of people or situations. As the new accessibility standards for ADA compliance are finalized, for example, those that might apply to consumer products will be included in these Guidelines for reference. In all cases, however, these values should be used as milestones and not as absolute or "good enough" design targets. If it is possible to go beyond the value and create a more accessible design, then that should be considered.

The Role of These Guidelines

The role of these Guidelines, then, is more to raise the awareness and understanding of designers and to help them ask the right questions than to provide specific answers or numbers. Notwithstanding, wherever specific design ideas or "recommendable" values do exist, they are provided. When they do not, general recommendations or design ideas are provided to help designers identify areas where attention can increase accessibility. In addition, data are provided when available to help designers measure the impact of various design decisions or tradeoffs.

The Role of the Designer

In all cases, however, the exact values to use for a given product design will have to be determined by balancing the various design factors and constraints for that particular product. They cannot be dictated a priori without picking a number which will be too restrictive for some designs and unnecessarily loose for others.

Solomon's Trap

Often, initial attempts at accessible design are done piecemeal. Accessible features are added where they are obvious rather than as a result of looking at the product's overall accessibility. The result can be a design which has accessible parts, but is not as a whole accessible or usable. Access to half a product when the rest is inaccessible is of little practical use.

In some cases, inspired by a desire to address the needs of people with different disabilities, it is even possible to design some parts of a device (such as the controls) to be more accessible to one population and design another part of the product with another disability in mind. Unless the whole product is accessible to at least one of these populations no-one is served.

In most cases it is possible with careful design to create products which are simultaneously accessible to people with different impairments. However, where this is not possible, care should be taken to be sure that the entire product is accessible to those disability populations that you are able to address. Giving half a product to one disability group and the other half of the product to another is not helpful to or desired by any of the disability groups.

Resolving Conflicting Recommendations

Sometimes a solution to a problem for one type of disability may cause a new problem for a person with another type of disability. For example, those with visual impairments may be helped by replacing a visual readout with auditory output, but this would in turn cause a problem for those with hearing impairments. As such situations arise, the Guidelines will attempt to highlight them and suggest ways to avoid or minimize any potential conflicts.

At the end of most sections, a summary of the recommendations, along with examples of balanced solutions, is presented. These are not the only, and perhaps not the best, solutions. They do, however, show how multiple recommendations can be addressed even when they seem to be contradictory. They also illustrate that it is usually impossible to follow all of the recommendations simultaneously.

NOTE: The ADA guidelines are currently under development and the ANSI standards for accessibility are currently under revision. When these activities are completed, specifications for minimum levels of accessibility for some types of structures and products will be spelled out. As these minimum values are defined they will be added to these guidelines in the sections to which they apply. To avoid confusion existing and proposed standards are not included in this draft.


SECTION 1: OUTPUT / DISPLAYS. Includes all means of presenting information to the user

Maximize the number of people who can/will ...

O-1 hear auditory output clearly enough.

O-2 not miss important information if they can't hear.

O-3 have line of sight to visual output and reach printed output.

O-4 see visual output clearly enough.

O-5 not miss important information if they can't see.

O-6 understand the output (visual, auditory, other).

O-7 view the output display without triggering a seizure.


O-1. Maximize the number of people who can... hear auditory output clearly enough.

Problem:

Information presented auditorially (e.g., synthesized speech, cuing and warning beeps, buzzers, tones, machine noises) may not be effectively heard.

Examples:

NOTE: Severely hearing impaired (and deaf) people cannot use audio output at all. See O-2 for guideline to address this problem.

Design Options and Ideas to Consider:

Additional Information:


Description of figure(s) in D-tag D

Figure O-1-a: A neck ring or ear loop can be plugged into a headphone jack on an audio source and provide direct inductive coupling between the audio source and a special induction coil on a person's hearing aid. This cuts out background noise that would be picked up by the hearing aid's microphone and provides clearer reception of the audio signal.


Description of figure(s) in D-tag D

Figure O-1-b: A headphone jack permits the connection of headphones, neck/ear loops, amplifiers or sound indication lights.


Description of figure(s) in D-tag D

Figure O-1-c: Speaker near edge and away from unwanted noise sources allows use of microphone to pick up sounds and relay on to an amplifier and speaker or neckloop. (Not as good as headphone jack.)


Description of figure(s) in D-tag D

On-screen bar graph (need non-visual method as well); Visual (and tactile) dot; Sliding Control with Reference (Not as good for people who are blind).

Figure O-1-d: Provision of a visual indicator of volume level is useful so that people with hearing impairments can better judge the impact of volume on others in the environment.


Figure O-1-e
Hearing Loss as a Function of Age

Description of figure(s) in D-tag D


Figure O-1-f
Hearing Loss for Different Frequencies as a Function of Age

Description of figure(s) in D-tag D


Figure O-1-g
Recommended Frequency for Altering Devices

Description of figure(s) in D-tag D


O-2. Maximize the number of people who will ... not miss important information if they can't hear.

Problem:

Audio output (e.g., synthesized speech, cuing and warning beeps, buzzers, tones) may not be heard at all or may be insufficient for effectively communicating information.

Examples:

Design Options and Ideas to Consider:

Additional Information:


Description of figure(s) in D-tag D

Figure O-2-a: LED next to speaker gives redundant visual indication of all auditory information.


Description of figure(s) in D-tag D

Figure O-2-b: A baby monitor from Fisher-Price provides a visual indication of the loudness of the sounds from the baby's room. [ It is advertised as being useful "even if you're surrounded by other noises, the TV, the phone, the vacuum, the dishwasher..." ]


Description of figure(s) in D-tag D

Figure O-2-c: A headphone jack permits the connection of visual and tactile indicators. It would also allow the connection of remote alerting devices which could be carried or positioned in other places in the house.


Description of figure(s) in D-tag D

Figure O-2-d: A visual indication of computer hard disk activity provides the same information to a person who is deaf that the disk noise provides to those who can hear. This feature is also useful to hearing users when the disk drive is silent or there is background noise.


O-3. Maximize the number of people who will ... have line of sight to visual output and can reach printed output.

Problem:

Visual displays or printouts may be unreadable due to their placement.

Examples:

Design Options and Ideas to Consider:

Additional Information:


O-4. Maximize the number of people who can ... see visual output clearly enough.

Problem:

Visual output (e.g., information presented on screens, paper printouts, cuing and warning lights or dials) may not be effectively seen.

Examples:

NOTE: See O-5 for guidelines for people who cannot use visual output at all. See O-6 for problems in understanding displayed output.

Design Options and Ideas to Consider:

Additional Information:


Description of figure(s) in D-tag D

Figure O-4-a: Ability to tolerate glare decreases sharply as a function of age as shown above. Data are based on a 1° glare source size and a background luminance of 1.6 fl. (Source: Bennett, 1977a, fig. 1.)


[Insert Chart Here] D

Figure O-4-b: By avoiding lines of confusion in the chromatic chart above one can circumvent problems with the major types of color blindness. For maximum visibility there should also be a high contrast between the figure (text) and background.


O-5. Maximize the number of people who will... not miss important information if they can't see.

Problem:

Visual output (e.g., information presented on screens, paper printouts, cuing and warning lights, and dials) may not be seen at all by some users.

Examples:

Design Options and Ideas to Consider:

Additional Information:


Description of figure(s) in D-tag D

Figure O-5-a: As the cost for voice synthesis continues to drop, a "Read Display" button could be included in appliances that have visual displays to allow them to be more easily and accurately read by people with visual impairments (low vision or blindness). For displays that are set (timers, etc.) the button should be pushable (for a quick read) or lockable (so that it would read out continually as it was adjusted).


Description of figure(s) in D-tag D

Figure O-5-b: If direct accessibility cannot be built in for some reason, an external connector would allow individuals with special interface devices to connect them. A relatively low cost and vandal resistant connector could be provided via an infra-red bidirectional link. Individuals who are blind or unable to read the displayed information could then use an assistive device and have information presented in auditory or tactile (braille) form.


O-6. Maximize the number of people who can ... understand the output (visual, auditory, other).

Problem:

Visual and/or auditory output may be confusing or hard to understand.

Examples:

Design Options and Ideas to Consider:

Additional Information:


[illustration will go here when ready] D

Figure O-6-a: Displays that use shorter sentences with careful use of white space, grouping of items, and a logical layout are easier to understand or interpret than displays that have too much text that is laid out in one font and block format.


O-7. Maximize the number of people who can ... view the output display without triggering a seizure.

Problem:

Individuals with seizure sensitivities (e.g., epilepsy) may be affected by screen cursor or display update frequencies, increasing the chance of a seizure while working on or near a display screen.

Design Options and Ideas to Consider:

Additional Information:


Description of figure(s) in D-tag D

Figure O-7-a: Percent of photosensitive patients in whom a photoconvulsive response was elicited by a 2 second train of flashes with eyes open and closed. As can be seen, the greatest sensitivity is at 20 Hz with a steep drop off at higher and lower frequencies. (Jeavons, P.M., and Harding, G.F.A. 1975)

*Recommendation added after original 1992 publication date.


SECTION 2: INPUT / CONTROLS. Includes keyboards and all other means of communicating to the device

Maximize the number of people who can ...

I-1 reach the controls.

I-2 find the individual controls/keys if they can't see them.

I-3 read the labels on the controls/keys.

I-4 determine the status or setting of the controls if they can't see them.

I-5 physically operate controls and other input mechanisms.

I-6 understand how to operate controls and other input mechanisms.

I-7 connect special alternative input devices.


I-1. Maximize the number of people who can ... reach the controls.

Problem:

Controls, keyboards, etc. may be unreachable or unusable.

Examples:

Design Options and Ideas to Consider:

Additional Information:


Figure I-1-a: Eye level anthropometrics. (Jones M.L. 1978)

Note: These are for an "average" woman in a wheelchair. Children and people with dwarfism would not have this reach or height. Also people with weakness caused by ALS, MS, MD and other impairments would have more limited reach.

[insert full page graphic here] D


Description of figure(s) in D-tag D

Figure I-1-b: Normal placement of stove controls poses serious reach and safety problems for individuals who are very short or in a wheelchair.


I-2. Maximize the number of people who can ... find the individual controls/keys if they can't see them.

Problem:

People with visual impairments may be unable to find controls.

Examples:

Design Options and Ideas to Consider:

Additional Information:


Description of figure(s) in D-tag D Keypad on which edge views below are based.

Figure I-2-a: The shape of a key or button can have a significant effect on people's ability to accurately locate (and operate) it.

Description of figure(s) in D-tag

A flat membrane or glass keypad provides no tactile indication as to where the keys are, even if you memorize the arrangement.

Description of figure(s) in D-tag

Providing a slight raised lip around the keys allows their location to be discerned easily by touch. The ridge around the key also helps prevent slipping off of the key when using a mouthstick, reacher, etc. to press the keys.

Description of figure(s) in D-tag

Raised bumps are tactilely discernable but it is harder to press the key without slipping off, particularly if you are using a mouthstick, reacher or other manipulative aid.

Description of figure(s) in D-tag

Raised keys with indents provide better feedback then just indents (as in example above) especially if the keys have different shapes or textures which correspond to their function.

Description of figure(s) in D-tag

Using indentations or hollows on the touchpad provides most of the advantage of ridges but is easier to clean. Hollows can be the same size as the key or of a consistent small circular size centered on the keys. Shallow edges such as those on the left button are harder to sense with fingers than the sharper curve of the middle button.


INSTRUCTIONS: For each keyboard below,visually locate the key on the right hand keyboard that corresponds to the marked key on the left. Note the increase in speed and accuracy when landmarks (nibs or breaks in the key patterns) are provided.

First keyboard: No landmarks except edges of keyboard.

Second keyboard: Nibs on keys used as landmarks.

Third keyboard: No landmarks

Fourth keyboard: Spacing used to provide landmarks.

Fifth keyboard: No landmarks

Sixth keyboard: Color or shading used to create landmarks.

Description of figure(s) in D-tag D

Figure I-2-b: Quick self-demonstration of the impact of landmarks on key-finding by people who cannot see labels on a key due to blindness or very low vision.


[Insert Blurred TV Control Panel Photo Here]
(Photo courtesy of John Ward) D

Figure I-2-c: Low Vision (blurred) View of a Television Control Panel

What button would you push to change the channel?

This television's control panel is undecipherable to people with low vision due to the layout, positioning of the channel vs volume controls (the buttons next to the channel display do not control the channel selection... they are the volume control buttons.), the use of abbreviations, the low contrast of the on/off switch and lack of a door to cover up the seldom used and confusing setup controls at the bottom. See Figure I-6-a for a drawing of this control panel (Answer: the channel control buttons are the two white triangles in the upper right, next to the on/off switch.)


I-3. Maximize the number of people who can ... read the labels on the controls/keys.

Problem:

Labels on controls, keys, etc. are difficult or impossible to see due to their size, color or location.

Examples:

Design Options and Ideas to Consider:

Additional Information:


I-4. Maximize the number of people who can ... determine the status or setting of the controls if they can't see them.

Problem:

Determination of control status or setting may depend solely on vision.

Example:

Design Options and Ideas to Consider:

Additional Information:


Figure I-4-a: The design of a knob can greatly affect its usability by people with low vision or blindness. D

Description of figure(s) in D-tag Description of figure(s) in D- tag Side view
  • No non-visual indication of setting. If vision blurred you cannot tell setting .
  • Difficult to put large print or braille labels on knob
  • (Also harder to grasp and requires twisting motion)
  • Highly visible raised pointer
  • Instant tactile indication of orientation allows setting to be read even if user is blind.
  • Easy to put larger print or braille labels on back panel.
  • Use of detents (large and small) can facilitate inter-numeral settings.
  • Black base disk provides high contrast and helps in control location/orientation on panel.
  • (Design is also easy to grasp and can be turned by pushing the point around - no twisting if the knob turns freely enough)

FOR EXAMPLE: What are the settings of the knobs below?

Description of figure(s) in D- tag


Figure I-4-b: Knob design can have substantial effect on usability by people who are blind.

Description of figure(s) in D-tag D

POOR: round smooth knob; no tactile orientation cue.

Description of figure(s) in D-tag

BETTER: has tactile orientation cue but user has to feel around to find it.

Description of figure(s) in D-tag

BETTER: orientation cue is less ambiguous. However the user must still feel the ends to be sure which is the pointer end.

Description of figure(s) in D-tag

BEST: has tactile orientation cue which is unambiguous and can be felt immediately upon grasping knob.


Description of figure(s) in D-tag D

Figure I-4-c: Sliding controls can be read but are more difficult since the person must find the slider and both ends of the range and then judge the ratio. Raised numbers would help.


Description of figure(s) in D-tag D

Figure I-4-d: Keypads allow direct and accurate setting of controls even if the person has no sight. However, this type of input is usually used with a digital display which would be inaccessible without a voice output option. Large high contrast numbers are helpful for low vision. A standard keypad layout is important.


I-5. Maximize the number of people who can ... physically operate controls and other input mechanisms.

Problem:

Controls (or other input mechanisms) may be difficult or impossible for those with physical disabilities to operate effectively.

Examples:

Design Options and Ideas to Consider:

Additional Information:

Comments on some common types of controls: (controls towards top of list are generally more accessible)

NOTE: Some diseases such as diabetes and "white finger" can cause loss of sensation in the fingertips. Therefore, controls that are dependent on tactile feedback should not rely on fine tactile sensation.



Description of figure(s) in D-tag D

Figure I-5-a: Individuals with arthritis, artificial hands, hooks, disabilities which restrict wrist rotation, or disabilities which cause weakness, have difficulty with knobs or controls that require twisting. Also difficult for people with loss of upper body strength, range of motion and flexibility as is common with elderly persons. Really should be avoided in bathrooms where soap and water create slippery environment. (Lever handles, now required in many building codes, facilitate access.)


Description of figure(s) in D-tag D

Figure I-5-b: Concave and non-slip buttons facilitate the use of manipulation devices, artificial hands, hooks and mouthsticks. This is especially true where pressure is required.


I-6. Maximize the number of people who can ... understand how to operate controls and other input mechanisms.

Problem:

The layout, labeling or method of operating controls and other input mechanisms can be confusing or unclear.

Examples:

Design Options and Ideas to Consider:

Reducing the number of controls.

Simplify the controls.

Making labels easy to understand.

Reducing, eliminating or providing cues for sequences.

Building on users' experiences (make the similarity obvious).

Additional Information:

Type 1 and 2 are obviously the most desirable especially for devices used in public places or devices which are seldom used. Type 3 or 4 may have to be used for some applications and more involved or specialized personal devices. Learning the meaning of the symbols would then have to take place in order to learn the operation of the device.

Figure I-6-a: This actual television control panel illustrates poor ergonomic design which would make the Television difficult to use for everyone, but particularly those with sensory and cognitive limitations. (See Figure I-2-c for a low vision look at this control panel)


Description of figure(s) in D-tag D
(all legends, capitalizations, etc., are exactly the same as real panel)

I-7. Maximize the number of people who can ... connect special alternative input devices.

Problem:

Standard controls (or other input mechanisms) cannot be made accessible for all of those with severe impairments.

Examples:

Design Options and Ideas to Consider:

Additional Information:


Figure I-7-a: By building a special "SerialKeys" option into a computers operating system software it is possible for users who cannot use the standard keyboard and mouse to create "authentic" keystrokes and mouse movements by sending signals into the computer's standard serial port. This would allow these individuals to access the computer and all of its software.

Description of figure(s) in D-tag D


Figure I-7-b: An infra-red bidirectional link could provide a low cost environment and vandal resistant mechanism for connecting assistive devices to information, control and transaction terminals.

Description of figure(s) in D-tag D

Individuals who are blind or unable to read the displayed information (as the individual on the left) could use an assistive device to have information presented in auditory or tactile (braille) form and to provide input to the terminal.

Individuals who are unable to operate the standard controls (as the individual on the right) could use an assistive device to control the terminal using an input system they can control (eyegaze, sip&puff, single switch scanning, etc.)


Figure I-7-c: An infra-red link could provide a more effective way for people with movement limitations to operate automatic "disability access" doors, and for people with vision limitations to operate and monitor the progress of elevators and other public access mechanisms.

Description of figure(s) in D-tag D

People who can drive their chairs but not operate the "disability access" push plates could open the doors with signals from their assistive devices. Similar ability to access and operate security keypads and other control panels in a persons environment would significantly decrease their dependence.

Description of figure(s) in D- tag

Individuals who cannot reach up and operate controls could operate them through their assistive devices.

The same infrared link could also provide information on the current floor number to people who are blind.


INPUT& CONTROL EXAMPLES: INTEGRATING THE GUIDELINES

Creating accessible input and control mechanisms that facilitate use by all people, particularly those with multiple disabilities requires careful balancing of the considerations. Below are some examples that demonstrate controls that integrate cross disability considerations in their design. Others will be added as the guidelines evolve. In some cases the design has more features than are necessary or has redundant features in order to demonstrate different possible combinations.

EXAMPLE 1: Wisconsin #1 Knot

Description of figure(s) in D-tag D

EXAMPLE 2

Poor Design

Description of figure(s) in D-tag D

Better Design

Description of figure(s) in D-tag


SECTION 3: MANIPULATIONS. Includes all actions that must be directly performed by a person inconcert with the device or for routine maintenance (e.g., inserting disk,loading tape, changing ink cartridge)

Maximize the number of people who can ...

M-1 physically insert and remove objects as required to operate a device.

M-2 physically handle and/or open the product.

M-3 remove, replace, or reposition often-used detachable parts.

M-4 understand how to carry out the manipulations necessary to use the product.


M-1. Maximize the number of individuals who can ... physically insert and/or remove objects as required in the operation of a device.

Problem:

Insertion and/or removal of objects required to operate some devices (e.g., diskettes, compact discs, cassette tapes, credit cards, keys, coins, currency) may be physically impossible. In addition, damage to the object or device can occur from unsuccessful attempts.

Examples:

Design Options and Ideas to Consider:

Facilitating orientation and insertion.

Facilitating removal.

Facilitating handling.

Additional Information:


Description of figure(s) in D-tag D

Figure M-1-a: Beveled slot facilitates insertion of cards, disks, etc. Tactile and visual cues should also be provided to indicate the proper orientation of the object to be inserted.


Description of figure(s) in D-tagD

Figure M-1-b: Mechanisms which eject items at least 1" and preferably 2" facilitate grasping of the item with tools, reachers, teeth or fists for those who cannot effectively use their hands/fingers.


Description of figure(s) in D-tag D

Figure M-1-c: Placing a stable surface under an insertion slot allow individuals to steady their hand when inserting an item. Be careful not to block access to the slot.


Description of figure(s) in D-tag D

Figure M-1-d: Phone jacks (such as found on headphones) are superior to two prong plugs because they can be inserted in any orientation and do not have to be twisted to align connectors.


Description of figure(s) in D-tagD

Figure M-1-e: Locks would be much easier to use if they used two faced keys and had self orienting bevels that would turn the key to the proper orientation to enter the slot. Alternately, keys which do not have to be oriented could be used.


Description of figure(s) in D-tag D
(Reachers: La Buda 1975)

Figure M-1-f: Different aids used for reaching and grasping include reachers, mouthsticks with special ends, artificial hands and hooks.


M-2. Maximize the number of people who can ... physically handle and/or open the product.

Problem:

Handles, doorknobs, drawers, trays, etc. may be impossible for some individuals to grasp or open.

Examples:

Design Options and Ideas to Consider:

Additional Information:


M-3. Maximize the number of people who can ... remove, replace, or reposition often-used detachable parts.

Problem:

Covers, lids and other detachable parts may be difficult to remove, replace, or reposition.

Examples:

Design Options and Ideas to Consider:

Additional Information:


M-4. Maximize the number of people who can ... understand how to carry out the manipulations necessary to use the product.

Problem:

Some individuals may have difficulty remembering how to operate the product, performing tasks in the correct order or within the required time, making choices, doing required measurements, or problem-solving.

Examples:

Some people (particularly those with learning disabilities or cognitive impairments):

Design Options and Ideas to Consider:

Many of the problems in this category are similar to the problems outlined in I-6 and many of the same design ideas would apply, including the following:

Other design suggestions include:

Additional Information:


SECTION 4: DOCUMENTATION. Primarily operating instructions

Maximize the number of people who can ...

D-1 access the documentation.

D-2 understand the documentation.


D-1. Maximize the number of people who can ... access the documentation.

Problem:

Printed documentation (e.g. operating or installation instructions) may not be readable.

Examples:

Design Options and Ideas to Consider:

Additional Information:


D-2. Maximize the number of people who can ... understand the documentation.

Problem: Printed documentation (e.g. operating or installation instructions) may not be understandable.

Examples:

Design Options and Ideas to Consider:

NOTE: See also O-6, I-6 and M-4.

Additional Information:

NOTE: See also additional information section in O-6, I-6 and M-4.


SECTION 5: SAFETY

Maximize the number of people who can ...

S-1 perceive hazard warnings.

S-2 use the product without injury due to unperceived hazards or user's lack of motor control.


S-1. Maximize the number of people who can ... perceive hazard warnings.

Problem:

Hazard warnings (alarms) are missed due to monosensory presentation or lack of understandability.

Examples:

Design Options and Ideas to Consider:

Additional Information:


S-2. Maximize the number of people who can ... use the product without injury due to unperceived hazards or user's lack of motor control.

Problem:

Users are injured because they are unaware of an "obvious" hazard or because they lack sufficient motor control to avoid hazards.

Examples:

Design Options and Ideas to Consider:

Additional Information:


REFERENCES and RESOURCES

Anderson, Thomas P., "Stroke and Cerebral Trauma: Medical Aspects," in Handbook of Severe Disability, edited by Walter C. Stolov and Michael R. Clowers. Washington, D.C.: U.S. Department of Education, Rehabilitation Services Administration, 1981.

Berkowitz, J.P., and Casali, S.P., "Influence of Age on the Ability to Hear Telephone Ringers of Different Spectral Content," Proceedings of the Human Factors Society 34th Annual Meeting, 1990, Vol. 1, pp. 132-136.

Corcoran, Paul J., "Neuromuscular Diseases," in Handbook of Severe Disability, edited by Walter C. Stolov and Michael R. Clowers. Washington, D.C.: U.S. Department of Education, Rehabilitation Services Administration, 1981.

Dreyfuse, H., Symbol Sourcebook: An Authoritative Guide to International Graphic Symbols, 1972.

Elkind, Jerome, "The Incidence of Disabilities in the United States," Human Factors, 1990, 32(4), pp. 397-405.

Friedmann, Lawrence W., "Amputation," in Handbook of Severe Disability, edited by Walter C. Stolov and Michael R. Clowers. Washington, D.C.: U.S. Department of Education, Rehabilitation Services Administration, 1981.

Grandjean, E., ed., Ergonomics of Computerized Offices. Bristol, Pa.: Taylor & Francis, 1987.

Halpern, Andrew S., "Mental Retardation," in Handbook of Severe Disability, edited by Walter C. Stolov and Michael R. Clowers. Washington, D.C.: U.S. Department of Education, Rehabilitation Services Administration, 1981.

Hare, B.A., and Hare, J.M., Teaching Young Handicapped Children: A Guide for Preschool and Elementary Grades. New York: Greene & Stratton, 1977.

Hoover, Richard E., and Bledsoe, C. Warren, "Blindness and Visual Impairments," in Handbook of Severe Disability, edited by Walter C. Stolov and Michael R. Clowers. Washington, D.C.: U.S. Department of Education, Rehabilitation Services Administration, 1981.

Hunt, R.M., "Determination of an Effective Tone Ringer Signal," paper presented at the 38th Convention of the Audio Engineering Society. New York: Audio Engineering Society, 1970.

Jeavons, P.M., Harding, GFA (1975). Photosensitive Epilepsy. (clinics in developmental medicine). London: Heinemann Medical.

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APPENDIX: GUIDELINES CHECKLISTS

Human Factors or Product Design departments in companies who manufacture consumer products may wish to develop checklists from these Guidelines for use by their design teams. As explained in Part III, the Guidelines were written as generically as possible in order to cover a very wide range of consumer products. Guidelines which are custom tailored to specific product lines would in fact be more useful to designers for that product line. It is possible to develop your own custom Guidelines to fit particular types of products or product lines, as discussed below.

Customization Process

As a first step you should determine which guidelines in the checklist apply to your product(s). For example, a design team for stereo systems may exclude from their checklist guideline O-2 (provide redundant visual output for all auditory information) because stereo systems are intended to provide sound which by its nature cannot be conveyed visually in any satisfactory way (as a standard part of the product). [A baby monitor however would not since it is not primarily an audio device but rather a baby activity monitor. A visual indication of sound from the baby is very useful. See fig O-2-b.]

Next, the "Design Options and Ideas to Consider" sections for each included guideline could serve as the basis for a checklist approach to meeting each guideline. Only those options which may apply to your product(s) would be included in the checklist. For example, the stereo product line checklist may exclude the following two design options included in the Guidelines for O-1:

Specific information from the "Additional Information" and "Illustrations" sections, as well as from your company's experienced designers, may yield additional options or more specifically-stated options than those furnished in the general Guidelines. For example, the stereo product line checklist may revise one option included in the O-1 guideline as follows:

Since your stereo equipment always has a volume control you could edit the first part out and focus in on the second topic in the sentence. It could also be "customized" to be more specific (using information from the "Additional Information" and "Illustrations" sections). Your new version might look like:

Example Checklists

In order to demonstrate several formats and customization approaches, this Appendix will contain several examples of checklists developed for specific product lines.

[EXAMPLES NOT YET COMPLETED]