Designing Human-Machine Interfaces For Vehicles Of The Future

A human-machine interface (HMI) is an interface that allows us to interact with a digital system. No matter what HMI we design, we need to allow users to take advantage of all that a system has to offer. For almost two decades, the personal computer was the first thing that came to mind when we heard about digital HMI. But the situation changed, and today HMI is an integral part of many devices we use daily — mobile phones, smartwatches, IoT devices, and even cars. Car HMI design is a relatively new field with its specifics that you need to be aware of.

My team has experience designing for major automotive companies like Mercedes-Benz and Mitsubishi, and we want to share some practical experience in this article. This article covers HMI car design, touching on why it is an essential aspect of car design.

What Is HMI? #

Car HMI is a collection of functional elements (such as head unit, instrument cluster, and head-up display (HUD) as well as interaction mediums (touch, voice, haptic) that allow turning the vehicle into a living space.

Brief History Of Digital HMI #

Digital HMI as we know them was initially introduced in the early 80s. At that time, the number of features that a regular vehicle was capable of doing was rising rapidly, and one of the tasks that designers had was to provide controls that allowed drivers to manage the new functionality. Designers follow two different approaches: some of them use analog controls (they add a physical button for each feature) while others add a screen with dynamic content.

The first approach was popular among German car manufacturers, while the second was popular among American and Japanese car manufacturers. One of the earliest examples of such systems was introduced in the 1986 Buick Riviera. This system allows users to control radio stations and climate using the monochromatic touchscreen display. It’s quite clear that the design of this system was inspired by the aircraft.

Benefits Of Using Digital HMI #

Digital HMI just recently became a mass-market technology. Just a few years ago, HMI was a prerogative of luxury vehicles. What is the reason why many car manufacturers suddenly decided to introduce displays in their vehicles?

The primary reason is money. It’s much easier to integrate a display in a cockpit and update the software once you see whether something works or doesn’t work for your users (similar to mobile phones) rather than design a set of physical controls and have to redesign it completely if something went wrong.

Another reason is market expectations — users expect to see HMI in the car they purchase today.

But those are market reasons, what about human needs? HMI has tremendous power to improve the user experience of drivers and passengers.

Here are just a few areas where HMI can be valuable:

  • Help drivers make informed decisions.
    HMI can provide real-time data to users in an easy-to-consume manner. Take electric vehicles, for example. A driver might be able to see just how much energy was used up in real-time based on how hard they accelerated the vehicle.
  • Can contribute to a safer driving experience.
    HMI can inform drivers about dangerous conditions (i.e. when the vehicle is close to the lane limit) and prevent driving collisions (i.e. slow down the car to avoid car accidents).
  • More natural interaction between the driver and the car.
    HMI can establish a more natural interaction between humans and machines. For example, a voice-based system can allow drivers to use natural words to give commands to the car.