Written by Conjure's CEO Sam Clark
Forgotten Lessons
As World War Two came to a close Alphonse Chapanis, armed with a freshly minted PHD in psychology, teamed up with Air Force Psychologist Paul Fitts to try and understand why over 400 B-17 Flying Fortress bombers crashed on landing in near identical circumstances. After many interviews and a cockpit investigation it transpired that tired pilots were activating the flaps down switch instead of the gear switch moments before touchdown. The result was catastrophic belly landings with sometimes fatal results.
Chapanis found the two switches were identical in shape and placed within fifteen centimetres of each other, making mis-identification by touch all too easy in the final moments of the landing sequence. To remedy this he attached a wheel to the end of the gear switch and a triangle to the flap switch, vastly improving recognition by touch and ushering in the field of shape coding as well as the concept of designer error. Aviation cockpit design follows these principles to this day.
Eighty years later in 2015 Ford’s luxury arm, Lincoln, had failed to learn these past lessons. Their Lincoln MKC SUV underwent a 13,500 vehicle recall as drivers were inadvertently turning their cars off while trying to enter sport mode. While there was no reported fatalities in this instance, the recall cost millions.
A Changed Landscape
Fast forward to the present day and the world of vehicle Human Machine Interface (HMI) design is facing its own reckoning with safety in the guise of rising driver distraction. The Cambrian explosion of touch screens in vehicles over the last decade has seen eyeballs increasingly on screens rather than the road ahead.
In 2022 Swedish auto magazine Vi Bilägare undertook tests including a 2005 Volvo and a Tesla Model 3 with tasks taking 10 seconds in the former and up to 23.5 on the latter.
Indeed the issue has become so bad that the European Transport Safety Authority (ETSC) is, from 2026, mandating the return to physical buttons for a range of vehicle functions including indicators, hazard lights, sounding the horn, operating windscreen wipers and activating the eCall SOS function. In the words of ETSCs strategy director Mathew Avery::
“New Euro NCAP tests due in 2026 will encourage manufacturers to use separate, physical controls for basic functions in an intuitive manner, limiting eyes-off-road time and therefore promoting safer driving.”
Failure to adhere to the revised guidance will mean vehicles won’t be able to achieve the highest five star safety rating, however it remains to be seen if OEMs will follow through with the recommendations as nothing is yet bound by law. To quote Frank Mutze from the ETSC:
“EuroNCAP requiring physical controls for some functions is a welcome step in the right direction. But we now need EU regulators to follow-up and adopt legally-binding requirements for all vehicles.”
While some OEMs such as Tesla and BYD have staked their brands on glass minimalism in HMI design, OEMs such as Volkswagen and Hyundai are part of a growing group rolling back their reliance on touch screens. In an interview with Korea’s JoongAng Daily, Ha Hak-soo, Hyundias VP of North America Design said:
“The company had been taken in by the “wow factor” of massive screens and had neglected the ease and convenience of physical buttons.”
“When we tested with our focus group, we realized that people get stressed, annoyed and steamed when they want to control something in a pinch but are unable to do so,”
So, with a one two punch of annoyed users and serious safety concerns it’s fair to say the all-screen HMI is likely to have been a short blip in auto HMI design history, and yet and while all this might feel like a step backwards for some, I feel there’s still innovation - And dare I say, fun - To be had with this regression.
A Sense of Theatre
The return to a more button-centered approach could well offer an opportunity for OEMs to bring more individualism and theatre into their driving experiences.
By way of example, the INEOS Grenadier has leaned in hard on the physical switch, with aviation styling, switch guards and chevrons all combining to create a military-like utilitarian finish in harmony with the vehicle’s rugged exterior.
The Grenadier also shares its overhead switch concept with the McLaren Speedtail. In the Speedtail’s case a series of overhead buttons including active dynamics, vehicle start and the v-max mode settings all add to the sense of theatre.
In both instances above there is an aviation-like feel to starting the vehicle with overhead switches which undoubtedly adds a “cool” factor to the driving experience.
Riffing on the aviation feel the Corvette Stingray combines a linear array of physical buttons in a sweeping right arch, dividing the driver and passenger and creating a distinctly cockpit-like feel.
I appreciate the above examples are luxury vehicles, but they serve as an example of how physical buttons can heighten the HMI experience. For that reason I welcome the return of the physical button, and hope OEMs will see their reintroduction as an opportunity rather than a mandated step backwards. At the same time, designers need to remember the lessons laid down by Alphonse Chapanis and those that followed, ensuring they elevate, not degenerate the driving experience.
