DEVELOPMENT AND VALIDATION OF PRINCIPLES OF UNIVERSAL DESIGN

Bettye Rose Connell, Mike Jones, Ron Mace, Jim Mueller, Abir Mullick, Elaine Ostroff, Jon Sanford, Ed Steinfield, Molly Story, & Gregg Vanderheiden

The Center for Universal Design, North Carolina State University, Raleigh, NC

ABSTRACT

The authors are involved in a collaborative effort to establish and validate universal design principles to guide a wide range of design disciplines including environments, products, and communications. Presented here are seven universal design principles useful for evaluating existing designs, guiding the design process, and educating both designers and consumers about the characteristics of more usable products and environments. Applications of these principles hold promise not only for improving the usefulness of commercial products for people with disabilities but also for broadening the market for assistive technology.

BACKGROUND

In our society, mass production and broad marketing have been used to reduce costs for consumers and generate profits for manufacturers. Because the market for products for disabled and older people is generally perceived as small and specialized, the advantages of mass production and marketing have not been realized. Specialized products and spaces designed only for people with disabilities and older people will always be more expensive, look different, and carry a certain stigma. Rather than continue to produce special and expensive products and environments, why not adopt a more "universal" design approach to the design of all products and environments?

Since the 1980s, a small but dedicated group of designers and advocates has been promoting the concept of universal design as a way to create products and environments that are more usable by everyone, regardless of age or disability. Universal design is a concept intended to increase the market for and, thus, production of products and environments that are usable by everyone to the greatest extent possible (Mace, 1985). By making more products and environments usable by more people, both the need for and higher cost of specialized products and environments is reduced (Mueller, 1990). And given the choice, all consumers are likely to prefer more usable products and environments.

Terms such as accessible, adaptable, barrier free, transgenerational, life span, and universal design have been used almost interchangeably. It is important, however, to distinguish universal design from other approaches used to achieve accessibility in products and environments. Universal design is a different approach with distinct advantages.

Accessible design refers to the design of specialized products, buildings, and exterior spaces to meet the needs of a selected segment of the total user population. Building code accessibility requirements are a good example of this approach. The distinguishing characteristic of accessible designs is that they typically are different from "normal" designs and, therefore, may contribute to segregation and stigma (e.g., handicapped entrance, seating, bathroom, etc.). Moreover, because they are different and often duplicative, these design solutions also tend to be more expensive.

Adaptable design refers to the design of certain products and environments to include features that can be readily adapted to the needs of particular users. A good example of adaptable design is the Braille overlays that some manufacturers provide for their appliances that can be used to make the display and controls legible to a person who is blind. The distinguishing characteristic of adaptable design solutions is that the existing product or environment must be adapted, adjusted, or added onto in order to make it more usable.

Universal Design can be defined as the design of products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialized design. While few products or environments are truly usable by everyone, certain designs are more usable that others in identifiable ways. Lever door handles, for example, are generally easier for more people to operate than are traditional door knobs; an automatic door opener is usable by anyone able to approach a doorway, making it a more universal solution.

The important characteristics of universal design solutions are that nothing needs to be added or adapted to make the product or environment more usable, these solutions do not segregate users, and in making the product or environment more usable by people with disabilities it does not become less usable by those who are not disabled. This last point is important because universal design approaches should be preferred by all users and, therefore, more widely marketable than existing designs.

Many products such as environmental controls and cordless telephones are useful both to people with and without disabilities. Similarly, many assistive technologies could have wider application than is currently being exploited. Certainly ramps are used as readily by people using strollers or moving furniture as by people using wheelchairs. Public telephones with volume control handsets assist people with hearing limitations but are also beneficial to anyone in a noisy environment. Expanding the market for assistive technology into commercial markets could help reduce the cost and stigma often associated with assistive technology.

STATEMENT OF THE PROBLEM

The universal design concept lacks established criteria to determine what makes for a more usable product or environment. Designers presently have only accessibility building codes and standards and limited human factors data to rely upon. At best, these sources provide minimum requirements or guidelines, which fall substantially short of ideal. To date, universal design has been described largely through example -- recognition of good designs that illustrate the concept. Guiding principles and specific design criteria are needed so designers have a clear understanding of what is meant by the concept, when it should be applied, and how to accomplish it.

Universal design principles should guide the design process and provide a benchmark against which to compare new designs for their universal usability. Providing the designer with universal design principles and criteria by which to evaluate his or her design would encourage a variety of design solutions rather than dictating one accessible solution to a given problem.

APPROACH

The authors are involved in a collaborative effort to establish and validate universal design principles to guide a wide range of design disciplines including environments, products, and communications. A working group of architects, product designers, and environmental design researchers has identified seven universal design principles for use in evaluating existing designs, guiding the design process, and educating both designers and consumers about the characteristics of more usable products and environments. The seven principles are presented here, in the following format: name of the principle, intended to be a concise and easily remembered statement of the key concept embodied in the principle; definition of the principle, a brief description of the principle's primary directive for design; and guidelines, a list of the key elements that should be present in a design which adheres to the principle. (Note: all guidelines may not be relevant to all designs.)

PRINCIPLE ONE: Equitable Use

The design is useful and marketable to any group of users.

Guidelines: 1a. Provide the same means of use for all users: identical whenever possible; equivalent when not. 1b. Avoid segregating or stigmatizing any users. 1c. Provisions for privacy, security, and safety should be equally available to all users.

PRINCIPLE TWO: Flexibility in Use

The design accommodates a wide range of individual preferences and abilities. Guidelines: 2a. Provide choice in methods of use. 2b. Accommodate right- or left-handed access and use. 2c. Facilitate the user's accuracy and precision. 2d. Provide adaptability to the user's pace.

PRINCIPLE THREE: Simple and Intuitive Use

Use of the design is easy to understand, regardless of the user's experience, knowledge, language skills, or current concentration level. Guidelines: 3a. Eliminate unnecessary complexity. 3b. Be consistent with user expectations and intuition. 3c. Accommodate a wide range of literacy and language skills. 3d. Arrange information consistent with its importance. 3e. Provide effective prompting for sequential actions. 3f. Provide timely feedback during and after task completion.

PRINCIPLE FOUR: Perceptible Information

The design communicates necessary information effectively to the user, regardless of ambient conditions or the user's sensory abilities. Guidelines: 4a. Use different modes (pictorial, verbal, tactile) for redundant presentation of essential information. 4b. Provide adequate contrast between essential information and its surroundings. 4c. Maximize "legibility" of essential information in all sensory modalities. 4d. Differentiate elements in ways that can be described (i.e., make it easy to give instructions or directions). 4e. Provide compatibility with a variety of techniques or devices used by people with sensory limitations.

PRINCIPLE FIVE: Tolerance for Error

The design minimizes hazards and the adverse consequences of accidental or unintended actions. Guidelines: 5a. Arrange elements to minimize hazards and errors: most used elements, most accessible; hazardous elements eliminated, isolated, or shielded. 5b. Provide warnings of hazards and errors. 5c. Provide fail safe features. 5d. Discourage unconscious action in tasks that require vigilance.

PRINCIPLE SIX: Low Physical Effort

The design can be used efficiently and comfortably and with a minimum of fatigue. Guidelines: 6a. Allow user to maintain a neutral body position. 6b. Use reasonable operating forces. 6c. Minimize repetitive actions. 6d. Minimize sustained physical effort.

PRINCIPLE SEVEN: Size and Space for Approach and Use

Appropriate size and space is provided for approach, reach, manipulation, and use regardless of user's body size, posture, or mobility. Guidelines: 7a. Provide a clear line of sight to important elements for any seated or standing user. 7b. Make reach to all components comfortable for any seated or standing user. 7c. Accommodate variations in hand and grip size. 7d. Provide adequate space for the use of assistive devices or personal assistance.

IMPLICATIONS

As noted, the principles of universal design are intended to assist in the evaluation of products, environments and communications, and to educate designers and consumers. To that end, work is currently underway to establish the validity of the principles in these applications.

The development and promulgation of principles of universal design has several implications for the design of assistive technology. Their presentation to RESNA is intended to prompt discussion concerning at least three:

1. To what extent can the need for assistive technology be reduced by making all products and environments more universally usable?

2. How can these principles be used to promote compatibility with and, therefore, facilitate use of assistive technology?

3. How can the market demand for assistive technology be increased by incorporating universal design features to broaden its applicability and appeal?

DISCUSSION

It must be acknowledged that the principles of universal design in no way comprise all criteria for good design, only universally usable design. Certainly, other factors are important, such as aesthetics, cost, safety, gender and cultural appropriateness, and these aspects should be taken into consideration as well when designing. Whenever possible, however, attempting to broaden the market beyond strictly people with disabilities or those who are older will increase the size of the market. It can reduce the cost of the product, and reduce the segregation and stigma that may be associated with it.

The universal design principles and related guidelines can provide an important starting point but by no means a complete solution to creating a more universally usable world. Adherence to these principles does not replace the need to involve consumers in the design process to the greatest extent possible. By the same token, encouraging designers to embrace a more empathic approach and view their work from the perspective of the full range of prospective users is an important step in the right direction.

REFERENCES

Mace, R. (1985). Universal Design: Barrier Free Environments for Everyone. Designers West, 33(1).

Mueller, J.L. (1990). "Real" consumers just aren't normal. The Journal of Consumer Marketing, 7(1), 51-53.

ACKNOWLEDGMENTS

Funding for this project was provided by the National Institute on Disability and Rehabilitation Research.

Molly Follette Story The Center for Universal Design North Carolina State University, Box 8613 Raleigh, NC 27695-8613 USA (919) 515-3082 molly_story@ncsu.edu