Inclusive Design | C1.2

Inclusive design (also called universal design, accessible design, or design for all) is an approach that removes barriers and ensures products and environments are usable by everyone, regardless of age, ability, or physical or cognitive difference. The goal is mainstream products that work for all users — not a parallel range of "special needs" versions that stigmatise users and add cost.

The term Universal Design was coined by architect Ron Mace in 1998. The Centre for Universal Design at North Carolina State University defines it as: "the design of products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialised design."

Inclusive design extends User-Centred Design (UCD) by deliberately including community members who might otherwise be overlooked: the elderly, pregnant women, people with disabilities, and those who are temporarily injured. The seven principles of Universal Design are:

1. Equitable use — the design is useful and marketable to people with diverse abilities
2. Flexibility in use — accommodates a wide range of individual preferences and abilities
3. Simple and intuitive use — easy to understand regardless of experience, knowledge, language or concentration level
4. Perceptible information — communicates necessary information effectively regardless of ambient conditions or the user's sensory abilities
5. Tolerance for error — minimises hazards and adverse consequences of accidental or unintended actions
6. Low physical effort — can be used efficiently and comfortably with minimal fatigue
7. Size and space for approach and use — appropriate size and space is provided regardless of the user's body size, posture or mobility

Legislation: Many countries legally require designers to consider users with disabilities:

• Americans with Disabilities Act (1990) — US federal law covering physical access, employment and product accessibility
• Disability Discrimination Act (1992) — Australian legislation requiring reasonable adjustment for people with disabilities
• Similar legislation exists in Canada, South Africa and India

包容性设计（也称为通用设计、无障碍设计或全民设计）是一种旨在消除障碍、确保产品和环境无论年龄、能力或身体、认知差异，人人可用的方法。目标是适合所有用户的主流产品——而不是歧视用户、增加成本的"特殊需求"替代版本。

通用设计一词由建筑师罗恩·梅斯于1998年提出。北卡罗来纳州立大学通用设计中心将其定义为："产品和环境的设计，在最大可能范围内，让所有人无需适应或专门设计即可使用。"

包容性设计扩展了以用户为中心的设计（UCD），特意包括了那些可能被遗忘的社区成员：老年人、孕妇、残障人士和暂时受伤的人。通用设计七项原则是：

1. 公平使用 — 设计对具有不同能力的人都有用且具有吸引力
2. 灵活使用 — 适应广泛的个人偏好和能力
3. 简单直观 — 无论经验、知识、语言或注意力水平如何，都易于理解
4. 可感知的信息 — 无论环境条件或用户的感官能力如何，都能有效传达必要信息
5. 容错性 — 最大限度地减少意外或无意行为的危险和不良后果
6. 低体力消耗 — 能够以最小疲劳高效舒适地使用
7. 使用的尺寸和空间 — 无论用户的体型、姿势或灵活性如何，都提供适当的尺寸和空间

立法：许多国家在法律上要求设计师考虑残障用户：

• 美国残疾人法案（1990年） — 美国联邦法律，涵盖物理访问、就业和产品无障碍性
• 残疾歧视法案（1992年） — 澳大利亚立法，要求对残障人士进行合理调整
• 加拿大、南非和印度也有类似立法

Inclusive design is a goal, not always a guarantee. Two realities place practical limits on how far universal solutions can extend.

The problem with designing for the average: Anthropometric data is reported as percentiles. The 50th percentile is the median — the value below which 50% of the measured population falls. Designing for the "average" person seems logical, but the Union soldiers census of 1850 illustrates the problem: the average height was 5 feet 8 inches, yet it is unlikely that any individual soldier was exactly that height across all relevant body dimensions simultaneously. The statistical average is not a real person.

Body dimensions are not linearly correlated: Someone with short arms does not necessarily have short legs. A person might be 5th percentile in arm reach but 95th percentile in torso height. This means:

• There is no such thing as an "average person" in any practically meaningful sense
• A product designed for the 50th percentile in every dimension will fit very few real people precisely
• Designing for one dimension in isolation can create problems in another

The 5th–95th percentile range: In practice, designers target the central 90% of the population. This means the product must be usable by the smallest plausible user (5th percentile in the critical dimension) and the largest (95th percentile). A seat, for example, needs adjustability to serve both the smallest and tallest users within this range.

Users outside this range — below the 5th or above the 95th percentile — will always require specialist or adapted solutions. This is not a failure of inclusive design but an honest acknowledgement of its practical limits. Designers must identify where the boundary is drawn and be prepared to justify it.

包容性设计是一个目标，而非总是能保证实现的结果。两个现实限制了通用解决方案能够走多远。

为平均值设计的问题：人体测量数据以百分位数形式报告。第50百分位数是中位数——50%的被测人群落在其以下的值。为"平均"人设计看似合理，但1850年联邦军士兵人口普查说明了这个问题：平均身高为5英尺8英寸，但任何个别士兵不太可能同时在所有相关身体维度上都恰好是这个数值。统计平均值不是真实的人。

身体尺寸不是线性相关的：手臂短的人不一定腿也短。一个人的手臂伸展可能是第5百分位数，但躯干高度可能是第95百分位数。这意味着：

• 在任何实际意义上都不存在"平均人"
• 针对每个维度的第50百分位数设计的产品将很少能精确适合真实的人
• 孤立地为一个维度设计可能在另一个维度上产生问题

第5至第95百分位数范围：实际上，设计师的目标是90%的核心人口。这意味着产品必须对最小的合理用户（关键维度的第5百分位数）和最大的用户（第95百分位数）都可用。例如，座椅需要可调节性，以服务于该范围内最矮和最高的用户。

该范围之外的用户——低于第5或高于第95百分位数——将始终需要专门或改良的解决方案。这不是包容性设计的失败，而是对其实际局限性的诚实承认。设计师必须确定划定界限的位置，并准备好为此辩护。

When a fully universal solution is not achievable, the design for extremes strategy offers a powerful alternative. Rather than designing for a middle-ground average, designers target users with the most demanding needs — those with physical, sensory or cognitive impairments. The key insight is that solutions developed for extreme users frequently become innovations that benefit the entire population.

This is known as the curb-cut effect: kerb ramps installed for wheelchair users are also used by parents with pushchairs, delivery workers with trolleys, cyclists and people with temporary injuries. The solution built for the hardest case improves the experience for everyone.

Examples from the chapter:

• Oxo Good Grips vegetable peeler: Sam Farber developed the peeler after watching his wife, who had arthritis, struggle to grip a standard peeler. The arthritic hand — the extreme user — required less grip force, a non-slip surface and pressure distributed away from the finger joints. The solution was an oversized handle made from Santoprene (a thermoplastic elastomer) with a scooped-out body and fins for thumb and forefinger, usable with a palm grip rather than a finger grip. The peeler became comfortable for everyone and entered the MoMA permanent collection in 1994. Its principles now appear across the entire Good Grips range and throughout the kitchen tools industry.
• Voice commands and text-to-speech (TTS): Developed for people with visual impairments and dyslexia, TTS reads digital text aloud. The hard constraint — the user cannot read a screen — forced a complete rethinking of human-device interaction. The result is used by millions without any disability for hands-free operation while driving, cooking or multitasking. Virtual assistants (Siri, Google Assistant, Alexa) are mainstream products built entirely on accessibility-driven innovation.
• Tactile pavements: Raised textured surfaces on walkways and platform edges warn visually impaired pedestrians — detectable by cane or foot — that they are approaching a hazard. They also alert any distracted pedestrian nearing a road crossing or platform edge.
• Rumble strips (Audio Tactile Lane Markings): Raised patterns along road edges generate audible and tactile warnings when a tyre crosses them. Designed primarily to alert drowsy or distracted drivers, they provide an additional safety layer for all drivers on long journeys or in adverse weather.
• Braille-like dots on Australian polymer banknotes: Tactile features help visually impaired users identify denominations and benefit all users through a consistent, identifiable surface feature.

Why design for extremes works:

• Hard constraints imposed by extreme users force genuinely new thinking rather than incremental improvement of the status quo
• Solutions that satisfy the most demanding users automatically satisfy less demanding users too
• It future-proofs products: ageing populations, temporary injuries and changing user profiles all shift today's "extreme" toward tomorrow's mainstream

当完全通用的解决方案无法实现时，为极端用户设计策略提供了一个强有力的替代方案。设计师不是为中间的平均值设计，而是针对需求最苛刻的用户——那些身体、感官或认知障碍的人。关键洞察是：为极端用户开发的解决方案经常成为使整个人群受益的创新。

这被称为路缘切割效应：为轮椅用户安装的路缘坡道也被推婴儿车的父母、推手推车的送货员、骑自行车的人和有临时伤害的人使用。为最困难情况构建的解决方案改善了所有人的体验。

章节中的例子：

• Oxo Good Grips蔬菜削皮器：山姆·法伯在观察到患有关节炎的妻子难以握持标准削皮器后开发了这款产品。关节炎手——极端用户——需要更小的握力、防滑表面和将压力分散远离指关节。解决方案是用Santoprene（一种热塑性弹性体）制成的加大手柄，带有挖空主体和拇指食指鳍片，可用手掌握持而非用手指握持。这款削皮器对所有人都更舒适，并于1994年进入MoMA永久收藏。其原则现在出现在整个Good Grips系列和整个厨具行业中。
• 语音命令和文字转语音（TTS）：为视觉障碍和阅读障碍用户开发，TTS大声朗读数字文本。硬性约束——用户无法阅读屏幕——迫使对人机交互进行彻底重新思考。结果被数百万没有任何残疾的人用于驾车、烹饪或多任务处理时的免提操作。虚拟助手（Siri、Google Assistant、Alexa）是完全建立在无障碍驱动创新上的主流产品。
• 触觉铺路砖：人行道和站台边缘的凸纹表面通过拐杖或脚可感知地警告视觉障碍行人他们正在接近危险。它们也会提醒任何接近路口或站台边缘的分心行人。
• 震动带（音频触觉车道标记）：沿路边的凸起图案在轮胎驶过时产生可听见和可感知的警告。主要为警告困倦或分心的司机而设计，为所有在长途旅行或恶劣天气中的司机提供额外的安全层。
• 澳大利亚高分子钞票上的盲文圆点：帮助视觉障碍用户识别面额的触觉特征，同时通过一致、可识别的表面特征使所有用户受益。

为什么为极端用户设计有效：

• 极端用户施加的硬性约束迫使真正的新思维，而非对现状的渐进式改进
• 满足要求最苛刻用户的解决方案自动也满足要求较低的用户
• 它使产品面向未来：老龄化人口、临时伤害和不断变化的用户概况都使今天的"极端"向明天的主流转移