Accessibility focuses on people’s ability to use a product regardless of abilities. Usability focuses on measuring the ease of use, learnability, and efficiency of the product. Accessibility is typically treated as a yes/no question with legal overtones. Usability focuses on measurement so any answer falls on a continuum. When discussing kiosks, centering solely on accessibility limits the conversation, particularly since the legal requirements are not clearly spelled out for many types of kiosks. This post focuses on kiosk usability, pulling from the available guidelines and best practices for kiosks.
Best practices / standards in kiosk design are available from a number of sources. A list of sources to start with includes the following:
- Section 707 Automatic Teller Machines and Fare Machines of Americans with Disabilities Act (ADA) Guidelines
- Section 508
- WCAG 2.1 A/AA
- Title 14 382.57 ACAA (Air Carrier Access Act)
These may be legal requirements for your kiosk depending on a number of factors but even if they are not, they provide detailed measurements and information to create a great user experience.
Kiosks are self-contained systems. While they may have an HTML based interface (not all do), users expect a different interaction from what they experience on the internet. Their expectations will also differ based on the kiosk purpose, location, and hardware enclosure. A key user expectation with kiosks is that use will be fast and intuitive. That means that kiosks should be designed to:
- Make it as easy as possible to complete the task without instruction
- Help a user through the task if needed
- Allow users to complete the task quickly after multiple uses
These expectations apply regardless of whether the user has a disability, but the differences in the needs and interaction style of individuals with disabilities means you should consider each disability use case separately to ensure as many people as possible have a successful user experience. Because ease of use and efficiency can cause conflicting needs, make sure you test both novice and expert user personas when conducting usability testing.
Creating a high quality user experience for individuals with disabilities requires considering each functional use case. The breakdown below is adapted from the Functional Performance Requirements from Section 508.
Individuals without vision
Individuals without vision interact with kiosks using text-to-speech technology.
- Text-to-speech technology be available
- Braille labels that include instructions on how to start the text-to-speech technology
- Text-to-speech technology start when a standard headphone is inserted
- The user experience to be comparable to all content on the kiosk including visual cues and printed receipts
To create a great user experience, the speech output needs to include enough help to guide the user through the process while avoiding useless information. For example, some content that makes sense on the web such as distinguishing between links and buttons is often not useful in the kiosk context. An orientation to the kiosk should be available up front but allow the user to easily skip it if they’ve used the kiosk before. Similarly, context sensitive help should be at the end of the speech strings so it is available if needed but doesn’t force the user to listen if it is not needed.
Controls that allow a user to distinguish between them by touch should be available and should allow the user to easily move through the content in a logical manner. Right and left arrows can be used to move between items and up and down arrows to move between sections. Standardizing these controls would make an easier user experience but the industry has not yet standardized to a particular set up.
Individuals with limited vision
Individuals with limited vision may be most successful if the kiosk provides a way to zoom the contents or increase the text/icon size, but this is not a standard requirement or provision. Standards do require displays include high contrast text in a san-serif font, typically at least 3/16th of an inch high. In addition, labels and keys on the kiosk should have sufficient contrast to be easily readable.
Individuals with limited vision may benefit from using the text-to-speech technology to help guide them. A use case where someone can see the screen and use touch capabilities at the same time as the text-to-speech is active is useful. This particular scenario also helps when someone without vision uses a kiosk with a sighted assistant. In addition to creating a larger, high contrast display, users with limited vision also benefit from the kiosk being positioned to avoid glare.
Individuals who can’t perceive color
Standards and best practices to support individuals who cannot perceive color require that instructions and content avoid relying on color alone to convey information. For example, kiosk instructions should not tell a user to hit a red button or pick up a receipt from the green tray when other buttons and trays of a different color exist. This doesn’t mean that color can’t be used but it should never be the only distinguishing factor.
Individuals without hearing and with limited hearing
Individuals without hearing or with limited hearing will be successful using kiosk as long as the kiosk does not rely on audio content or queues. Standards require kiosk content with audio to include captions and recommend a location for the caption controls. In addition, standards require volume control when private listening is available and incremental volume up to at least 65 decibels where the volume is reset to default after every use.
Individuals without speech
If a kiosk requires speech for interaction, a best practice is to provide an alternative such as keyboard input to support individuals without speech. This alternative also supports individuals with privacy concerns who do not wish to say something in a public setting. Medical kiosks, financial kiosks and other kiosks that deal with sensitive information should consider the risks associated with voice interaction as well as accessibility ramifications. For example, clear indicators are needed for when microphones are active.
Individuals with limited reach, manipulation and strength
Individuals with limited reach, such as wheel chair users, need controls to be located between 15 and 48 inches from the floor if there is nothing the user needs to reach over (the max height is 44 for obstructed forward reach and 46 for obstructed side reach). Displays should be visible from 40 inches above the floor. Wheel chair users also require a stable, slip proof approach that is wide enough to allow for a wheelchair. Individuals with limited manipulation and strength require controls that are easy to push, pull, turn or otherwise interact with. Users should be able to use the kiosk without tightly grasping, pinching or twisting their wrist.
Individuals with limited language, cognitive, and learning abilities
Kiosks should support individuals with cognitive and learning disabilities by providing plain language instructions, labels and content. Providing consistent imagery to supplement text and simple concepts to supplement numbers will also be helpful. While still in draft, “Making content usable for people with cognitive and learning disabilities” provides detailed best practices in this area.
For each functional area, the user should be able to successfully use the kiosk in a reasonable amount of time. This may not always be as fast as someone without a disability but it should be close. This requires user testing to ensure success.
Kiosks include three general components that need to be considered from a usability standpoint:
- The kiosk hardware which includes the shell, the display screen, and any other input and output devices
- The kiosk software which includes the primary software and any additional assistive technology incorporated into the kiosk
- The kiosk location which is where the kiosk will be used.
To be successful, you need to consider accessibility and usability in each of these components. The kiosk hardware needs to consider height and reach, labeling, navigation, input and output. The kiosk software needs to address contrast, captions, plain language, speech, and other assistive technology. The kiosk location needs to address approach, glare, noise and privacy. Each stage is critical. An accessible kiosk in an inaccessible location is useless as is an inaccessible kiosk in an accessible location. Often different groups within an organization are responsible for each separate component so clearly articulating the need for accessibility and conducting testing throughout the process and upon deployment is critical.