Ron Mace defines the universal design (UD) 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."
The seven principles of UD below have been developed accordingly to the definition.
Principle 1: Equitable Use
Principle 2: Flexibility in Use
Principle 3: Simple and Intuitive
Principle 4: Perceptible Information
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Principle 5: Tolerance for Error
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Principle 6: Low Physical Effort
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Principle 7: Size and Space for Approach and Use