The appearance of smart automotive human-machine interfaces (HMI) was an inevitable development. People are used to being able to perform all kinds of actions with their smartphones, and extending that capability to their cars is natural. Progress has been rapid in some ways, cautious in others. There’s been more technology available for news and entertainment than for the core functions of a car. However, significant changes are already underway, as touchscreens and voice commands play an increasing role.

Security, safety, and privacy are important issues. The last thing anyone wants is a car crash because of a human-interface problem. Anything that affects a vehicle’s operation will need extensive testing before being allowed on the road.

The early history

The history of automotive HMIs goes back a surprisingly long way. The term is vague; technically, a steering wheel is a human-machine interface. But generally the term refers to technology that adds some intelligence to the interaction. In 1966, General Motors experimented with a Driver Aid, Information, and Routing (DAIR) system, using punch cards in the car and sensors built into roads. Nissan had a heads-up display (HUD) in its 1989 240SX.

From smartphones to cars

Today’s work on HMIs is based on smartphone technology. It usually relies on mobile operating systems such as Android and iOS. In many cases, the phone has remained the primary device, adding an interface layer to the car’s systems and controls. Voice and touchscreen interfaces let the driver get navigation information, adjust the thermostat, or play music without touching the phone.

The needs of a car’s HMI dictate a different approach from typical phone applications. The interface has to be as simple as possible. Anything that requires more than a quick glance would be dangerous. The value of voice controls is obvious, but caution is needed there too. Children might think it’s fun to experiment with the voice interface at 60 MPH.

In the long run, computing power in the car will increase safety. Voice control lets people make calls without touching their phones at all. Voice input and a HUD reduce the need to look away from the road. In the future, driver monitoring will let people know when they need to stop for a nap.

The main functionality is going to move into the car itself, with its own cell connection. That will allow the development of more car-specific operating systems and applications, as well as closer integration with the vehicle.

Market status

Prescient Market Intelligence estimated the size of the global 2017 automotive HMI market at $13.9 million. Touch screen displays have generated the most revenue, but heads-up displays are growing rapidly. HUDs are starting to move into mid-priced vehicles. PSI predicts an annual growth rate of 13.8%.

”Multimodal” is a buzzword with growing popularity. It simply means having a variety of input modes, but it usually applies to the more advanced modes, such as voice. Concepts such as a holographic display operated by air gestures have been demonstrated at trade shows. Multimodal systems, according to PSI, are gaining in market share.

Mercedes’ MBUX

Not surprisingly, the most elaborate HMIs have appeared first in high-priced cars. The Mercedes-Benz User Experience (MBUX) has appeared in the new A-Class line of cars. It lets the driver control lighting and temperature, connect to a cell phone, access the Internet, and perform navigation. There are two dashboard displays. The optional HUD appears on the windshield, its position and content under driver control.

The underlying hardware has a lot of power, with a 6-core CPU, two Nvidia graphics chips, and 8 gigabytes of RAM. Mercedes plans to bring MBUX to all its cars in the next few years.

Android Auto

Google has been heavily involved in automotive computing since 2013. Currently, Android Auto is an HMI layer that sits on top of Android in a phone and connects to a car’s systems. The ”N” release of Android will add features supporting automotive integration into the operating system itself, letting it work without a separate phone. With an open platform, Google expects that many independent developers will add to its value. Guidelines for developers let them extend applications for use with Android Auto.

The dashboard screen consists of notifications and control icons, so it isn’t a straightforward imitation of the phone’s screen. Applications need to add functionality using the HMI API in order to do anything on the dashboard.

Patrick Brady, the director of engineering for Android Auto, says that many cars are already ”using Android under the hood” — literally! This includes all the new cars from Hyundai and Honda, with General Motors following soon.

Apple CarPlay

Apple’s approach with CarPlay is similar, in that the electronics in the car get their functionality from a connected iPhone. However, the dashboard screen looks more like a normal iOS screen, with application icons. Many cars support both Android Auto and CarPlay.

Applications have to be enabled for CarPlay. It works with the car’s controls, to the extent that its interface allows. Siri voice control is another option, and Apple strongly encourages its use. Supported cars let the driver activate Siri with a button on the steering wheel. Car manufacturers can provide applications that are specific to their models. Apple has always been strict about permitting applications on the App Store only if they meet its guidelines, and developers should expect it to be especially strict on anything that runs in a car.

What to expect next

Touchscreens are rapidly becoming available in many new car models. The next step will be full functionality without the need to connect a smartphone.

Artificial intelligence will play a growing role. Voice input systems already recognize indirect requests, such as ”It’s too cold.” Vehicle analytics will give drivers more useful warnings than the cryptic Check Engine light. These features will increase safety and reliability.

The best options are found in high-end cars, but as the electronics become less expensive, their benefits will diffuse to mid-range cars and eventually to nearly all models. Within a decade, being able to talk to our cars will be as natural and common as the features of a smartphone are today.