WCAG (Level A) SC 2.5.4 Motion Actuation (w3.org)
Issue description
WCAG 2.5.4, “Motion Actuation” addresses the accessibility of functionality that is triggered by device motion or user movement, such as shaking or tilting a device. While these interactions can be engaging and intuitive for some users, they can pose challenges for others.
Some websites and applications use motion actuation for:
- Game controls: Shaking the device to control a game character or activate a power-up.
- Navigation: Tilting the device to navigate through a menu or scroll through content.
- Input actions: Shaking the device to undo an action or submit a form.
However, this can create barriers for people with:
- Motor impairments: Users with limited mobility, tremors, or other motor impairments might find it difficult or impossible to perform the required motions.
- Vestibular disorders: Motion actuation can trigger dizziness, nausea, or headaches for people with vestibular disorders.
- Situational limitations: Users might be in situations where moving their device is impractical or unsafe (e.g., on public transportation or while walking).
WCAG requirements
This guideline requires that any functionality that is triggered by motion actuation can also be operated by user interface components and the success of the activity does not depend on the speed or accuracy of the user movement. This means providing alternative ways to activate the same functionality, such as:
- Buttons or links: Provide on-screen buttons or links that users can click or tap to trigger the same action.
- Keyboard controls: Offer keyboard shortcuts or other keyboard interactions that replicate the functionality.
- Voice commands: If available, allow users to use voice commands to activate the functionality.
Essentially, this guideline ensures that users have alternative ways to interact with content that doesn’t rely on device motion or user movement. This promotes inclusivity and makes functionality accessible to a wider range of users, regardless of their physical abilities or situational constraints.
Who this issue impacts
Follow the links for additional information on user impairments:
Suggestions for remediation
Remediating WCAG 2.5.4, “Motion Actuation” involves providing alternative ways to access functionality that is triggered by device motion or user movement, ensuring that users who cannot perform these actions can still use the features. Here’s how:
Provide alternative input methods
- Buttons or links: Offer on-screen buttons or links that users can click or tap to activate the same functionality as the motion actuation.
- Keyboard controls: Provide keyboard shortcuts or other keyboard interactions that replicate the functionality.
- Voice commands: If available, allow users to use voice commands to activate the functionality.
Clear instructions and labeling
- Explain alternatives: Clearly explain to users that alternative input methods are available and how to use them.
- Label controls: Use clear and descriptive labels for buttons, links, or keyboard shortcuts that correspond to the motion-activated functionality.
Consider user preferences
- Disable motion actuation: Provide a setting that allows users to disable motion actuation entirely if they prefer not to use it.
- Customization: Allow users to customize the sensitivity or type of motion required to trigger the action, if feasible.
Testing
- Test alternative methods: Thoroughly test all alternative input methods to ensure they are functional and easy to use.
- Assistive technology testing: Test with assistive technologies to ensure that users can access and operate all functionality without needing to use motion actuation.
Examples
- Shake to undo: Provide an “Undo” button that users can click or tap, as well as a keyboard shortcut (e.g., Ctrl+Z) to perform the same action.
- Tilt to navigate: Offer on-screen buttons or arrow keys to navigate through content instead of relying on device tilt.
- Shake to refresh: Provide a “Refresh” button or a pull-to-refresh mechanism as an alternative to shaking the device.
By providing these alternatives, you ensure that all users, regardless of their physical abilities or preferences, can access and interact with the functionality of your website or application.
