Interaction principles

Interactions between a driver and a screen must be simple, non-distracting, and easily interrupted, so the driver’s attention can quickly return to the road.

This section describes how you can:

Keep information current and glanceable

To minimize the time drivers spend looking away from the road, onscreen information needs to be up-to-date and easy to understand at a glance:

Convey tasks & states at a glance

Drivers need to quickly understand tasks or system states by glancing at the screen. They should be able to read the content within 2 seconds and return their focus to the road.

Provide quick responses

Make sure that system response times after user input – for example, the time between a tap and the resulting ripple animation – do not exceed 0.25 seconds. If content takes more than 2 seconds to load, a spinner or similar interface change should indicate that the device is responding.

Provide timely, accurate driving information

Show relevant driving-task information immediately and accurately under normal driving conditions. Display any malfunction or safety status in real time.

Encourage hands-on driving

Safe driving requires that drivers keep their hands on the wheel as much as possible:

Use one-handed gestures

No operation should require removal of both hands from the steering wheel. Gestures (such as waving to interact with the system) should require only one hand and should not require any maneuvers that could negatively impact operation of the vehicle.

Allow hands-free speech interface

Speech-based communication systems should permit hands-free speaking and listening. Starting, ending, or interrupting a spoken dialog, however, can be done manually.

Simplify voice interactions

Design multistep voice interactions carefully to minimize driver distraction.

Prioritize driving tasks

The most important tasks a driver performs are those related to driving – everything else must be secondary:

Allow driver to control pace

Interaction sequences should be interruptible and resumable at logical points. The driver should control pacing.

Information needed for driving and safe vehicle control (such as navigation directions) should be prioritized over information unrelated to driving (such as media titles).

Consider non-driving content carefully

Information unrelated to driving (such as ads, social media content, web page content, books, periodicals, email, and subscription alerts) should be carefully considered to minimize driver distraction.

Prioritize sound & adjust volume for driving tasks

The interface should give priority to audio information that is critical to driving. For example, when navigation directions are being relayed, media volume should be lowered or ducked. In addition, users should always be able to fully adjust the volume down to a muted level.

Discourage distraction

Avoid pulling the driver’s attention away from the road for non-essential reasons:

Avoid hazardous or distracting activities

The system should not allow unnecessary and potentially hazardous activities, such as playing most games, manually surfing the internet, or participating in fitness activities involving unsafe hand or foot maneuvers while driving.

Avoid irrelevant movement

Avoid displaying dynamic visual information unrelated to driving, such as videos and auto-scrolling text. Carefully consider the use of animations to ensure they aid the driver’s situational understanding.