Bench Talk

Few other human-machine interfaces (HMIs) present as many challenges as the modern automobile, so have pity on the weary auto industry designer tasked with trying to come to grips with telematics. It’s only rival in complexity is the commercial airliner, whose flight deck remains chock full of knobs, dials, and switches even after wholesale changes that migrated functions to large touch screen displays like those in the Airbus 380 and Boeing 787 Dreamliner. At least pilots are highly trained, technically astute professionals, however, while drivers range from being technology haters to “enthusiasts” who like to tweak engine control modules for higher performance. Designing an interface that is usable by such a spectrum of drivers has got to be insanely difficult.

Figure 1: Flight deck of the Boeing 787-8 N787BA. By Alex Beltyukov, CC BY-SA 3.0,https://commons.wikimedia.org

Being a longstanding car lover and a bit of an annoyance to friends and relatives who’ve just bought a new car, I always ask to at least sit in it or ever better, to let me drive it. So I have driven the great German brands and various models from Honda, Toyota, Nissan, and Subaru. The variations amongst them are immense. There is no single or “standard” approach to the “modern” vehicle dashboard other than that they typically combine one or more touchscreens with a few buttons and sometimes redundancy, such as controls for audio on the steering wheel. This alone makes driving a someone else’s vehicle a trial-and-error experience.

One of the most egregious examples of how not to design a vehicle HMI is the Honda Civic, which until 2015 presented the driver with the usual instrument cluster (minus the speedometer) and above it a second array of displays including a digital speedometer, further “complemented” by a large touchscreen display on the center stack, with separate heating controls below it. Some of these functions can be displayed in more than one place, leaving it to the driver to determine what should be displayed where. This may be an extreme example, but it is far from the only one.

Admittedly, this criticism may be harsh, as there are so many functions (and subfunctions) to control, and not much space in which to do it. For my benefit, if no one else’s, I compiled a basic list in Table 1 of all functions and where (in my opinion at least) they are best placed. I left out features like seat heating and cooling, shift paddles, and a few infrequently used controls like traction control on/off that can be placed elsewhere.

Figure 2: Pre-2015  Honda Instrument cluster/dash.  Credit: Barry Manz.

Table 1: Where I Think Functions Should Be Placed

Even if I left some functions out, the question remains of how to implement them. Icons don’t work on a touchscreen, as they inevitably use a menu-driven approach, forcing the driver to “drill down” through many layers. A combination of touchscreens and a console-mounted wheel is no better, as it adds another control (the wheel) making the driver visually move back and forth between them. The standard approach of using every technology available (screens, buttons, voice control) requires you to know which technology does what.

Fortunately, designers are coming up with more elegant approaches, one of which I found fascinating. It was created by San Francisco-based designer Matthaeus Krenn, whose approach uses a single touchscreen to perform most but not all functions, or not yet. The approach is best understood by viewing Krenn’s video, which demonstrates that it can at present control up to eight primary functions along with their sub-functions. If you agree with the placement of functions in Table 1, eight is certainly enough for now.