See it, hear it, feel it: How driving assistants grab your attention

Today’s drivers are never alone. Our cars are increasingly equipped with assistance systems that offer feedback, some working silently in the background and others fighting for our attention. While these systems largely help the driver and even save lives, the challenge lies in creating convenient and unobtrusive systems that don’t divert our attention from the road or create safety issues. Identifying where the line is between driver distraction and driver assistance can be difficult. This is why it’s important to understand how each technology interacts with the driver, the purpose of the technology and the potential consequences of adding a certain feature to a vehicle’s driver assistance system. Failing to do any one of these steps could lead to much worse outcomes than simply customer dissatisfaction, potentially threatening passenger safety and causing irreparable damage to automakers.

Just because we have the technology to do something, doesn’t mean it’s going to make the driver experience better. As an industry, we need to take a holistic approach to driver assistance systems, examining each feature in light of the entire driver experience. So, below, we examine these systems before we offer some important advice on implementing them.

Driver assistance systems have been around since the early 1970s, when we saw the first anti-lock braking system (ABS). This was followed by traction control systems (TCS), electronic stability control (ESC) and adaptive cruise control (ACC) in the 1980s and 1990s. In the last decade, assistance systems began to help with steering via lane keeping assistance systems (LKAS) and collision avoidance systems (CAS). And now, parking assist systems can take over the steering wheel and override the throttle and brakes. 

While these systems have evolved, so have display features – the classic dashboard with a simple speedometer and dedicated light bulbs used as indications for vital electric functions is long gone. As technology has progressed, more advanced instrument panels have evolved and the displays have grown bigger. Now they are single, large displays behind the steering wheel, with some displays spanning pillar to pillar. But development hasn’t stopped there. Digital cockpits now often combine several displays in the car for a fully immersive information and entertainment experience.

All driver assistant features that either show or tell information can be boiled down into three feedback categories: visual, acoustic or haptic. Let’s take a look. 
 

VISUAL

Visual feedback, or optical feedback, is the most common type, and the possibilities are endless – as icons can quickly convey information by lighting up or changing color. While a single icon only takes a small space on the dashboard and many symbols are well-known or standardized, there is a danger in turning the dashboard into a ‘Christmas tree’ without adding much benefit. As the number of icons increases, the information can overwhelm drivers, causing them to neglect, misinterpret or fail to recognize vital information. 

Another example of visual feedback includes the display of texts. Error messages and warnings, especially as pop-ups, are common use-cases. Infotainment and navigation heavily depend on the display of texts for lists and menu options of all kinds and can be more expressive and not as ambiguous or cryptic as single icons. But text uses more space and requires more time and mental capacity to read. Plus, long texts can distract drivers and the language would need to be translated for foreign markets.

Bear in mind that for all optical feedback, drivers must take their eyes off the road to look at the display. This may not be true for head-up displays (HUDs), but HUDs interfere with the outer-world vision. Information presented in HUDs needs to be handled in a way that the driver can still see the road ahead and recognize the real-world traffic situation. 

The challenge lies in offering the driver enough information without producing a visual or mental overload. If more than one element shares space on a display, the question of priority arises. Thus, well-designed priority handling is essential for modern digital cockpits. Ideally, the priority handling is defined during the requirements phase, so that it can be tested and refined along with the development of the system.

ACOUSTIC

Acoustic feedback, or audible feedback, communicates with the driver through sounds and spoken announcements. For decades, acoustic feedback came from indicators – with that characteristic clicking sound. Now the clicking sound is electronically generated and is played using a small loudspeaker inside the dashboard or via the car’s sound system. The use of loudspeakers in the car has opened a whole new world of acoustic feedback. Now we can use any kind of sound, including spoken announcements, which present the message in a clear and concise way.

But spoken announcements are a double-edged sword. They can provide precise feedback in a way that users are familiar with because of the similar features available on phones and smart speakers. But there are drawbacks. Translations are necessary and language switching takes time. Long texts temporarily block the audio channel, and spoken announcements require increased development efforts to ensure announcements are precise, clear and understandable. In addition, sounds and other acoustic feedback trigger a psychological reaction known as “orienting response,” meaning, their attention is drawn to the sound—and away from what they were concentrating on before, causing drivers not to be in full control of their vehicles.

The effect can be minimized with careful creation of the sounds and spoken announcements. For example, a soothing intro sound before an announcement produces less distraction than a sudden yell from the loudspeakers. Still, it’s easy to overdo it with sounds. Adding more and more audible information leads to an acoustic overload. In the case of acoustic feedback, less is more. Similar to visual feedback, priority needs to be handled if two or more sources must use the audio channel at the same time.

HAPTIC

Haptic feedback can be useful for direct feedback on pedals, steering wheels, and seats but is only possible with equipment that is in direct or indirect contact with the driver. 

The first haptic feedback came about with ABS and was merely a necessity. When ABS actively controlled the pressure in the brake system, the driver felt the pressure changes pulsating in the brake pedal. With the arrival of new assistants, pedals today can alert the driver with a single stronger pulse, or the accelerator can be made stiffer to warn about speed limits. Pedals are a long-established feedback channel, but they provide only limited possibilities of feedback and may also be misinterpreted as mechanical malfunction. 

The steering wheel is also a common object to deliver haptic feedback, as it is logically connected to steering and can assist in lane keeping by making the steering harder to one side and lighter to the other. Collision avoidance systems can also alert the driver by adding a strong shaking to the steering wheel. 

The biggest object in contact with the driver is the driver seat. While some seats already come equipped with heating and massage functions, they’re not intuitively connected to a driving function and only reflect road conditions, like bumps or holes. Therefore, automakers who use seats for haptic feedback need to create the connection to driving functions in the driver’s mind; and education may be needed to create this connection, otherwise the feedback could become ambiguous.
 

Conclusion

Each feedback method has its advantages and disadvantages, presenting system designers with a lot of questions. For example, which feedback method should be chosen for a specific assistant? Are there brand-, culture- or market-specific settings to be considered? Which assistant comes first in a concurrent situation? Should information be filtered to not overwhelm the driver? And so on. Choosing the right method also depends on a number of other factors, like the driver's learning style, age group, and the need for standardized feedback to prevent confusion between different car models and brands.

To create a positive user experience and reduce distraction, it is essential to define international standards for feedback methods. Therefore, participating in relevant working groups and industry organizations can help shape future automotive standards for software-defined vehicles. This will avoid end-user confusion and increase the chances of user acceptance of digital assistants for safer mobility.

At Luxoft, we have recognized the importance of engaging in this issue. We actively participate in the DIN and ISO working groups, defining the upcoming national and international automotive standards, and we’re also a member of the Association for Standardization of Automation and Measuring Systems (ASAM e. V.) – engagements that will help us not only shape automotive standards, but guide the future of software-defined vehicles.

To learn more about Luxoft’s solutions that are accelerating the transformation to software-defined vehicles, visit luxoft.com/aumotive.