Great user experience doesn’t just consider the device and user in isolation, but also the environment and circumstances of use. This is particularly important in the automotive sector where distraction can be fatal and users need to be able to access important controls within seconds without looking away from the road. This is difficult to balance with the increasing complexity of modern vehicles.
In 2008, Mercedes-Benz released what, in my opinion, is the most refined automotive HMI (Human Machine Interface) user experience there is to this date. Sadly, the industry since took many steps backwards after this and started pivoting to highly distracting and unsafe capacitive touch controls instead, making that 2009 CL I used to have also my peak automotive user experience so far.
This is a overview of this experience and why I think it’s great, and should be an example for designers even today.
Control Overview
In the user experience Mercedes-Benz introduced in 2008, and produced until 2013, the Bedienkonzept (operating concept) is designed with the single most important thing in mind that automotive UX designers need to care about: minimizing the time the driver looks away from the road.
Layout
Everything is accessible via physical controls. The controls are laid out in a way that is just logical. Steering wheel controls operate driving and basic media/phone functions, seat adjustment controls are visible on the doors and are the shape of the seats. They’re physical so you can feel, which directions things can move. e.g. the headrest can only move up and down, so the little headrest model knob only moves up and down.
There are physical gear and wiper stalks, physical controls to the left of the steering wheel for lights and the night vision toggle button is intuitively right next to the light switch (Vision related! Makes sense.) Sunroof controls are physically located overhead, near the sunroof.
Climate controls are a neat row of physical controls for most commonly used functions. Parking assistance toggle is a dedicated physical button, so you can easily hit it when starting to park.
There’s a main control knob, located on the center console, for on-screen menus on the center display.
There are physical controls for things that are needed quickly. E.g. the “lift” to lift the suspension is a dedicated button because when the need to use it arises, there’s usually no time to find that function in some menu. Same for defrost/defog.
It’s ridiculous that I need to point that out, but the glove box can be opened with a physical latch on the glove box itself. It is similarly unfortunate that I have to point out that the window controls are physical knobs to move the windows, arranged in a four-corner layout, like the four windows of the car.
One could argue that the number of controls were a bit overkill and wouldn’t be needed. e.g. the lights and wipers are automatic anyway… But especially if once in a year I want to manually control either of those, I won’t necessarily know where they are. The physical light controls enabled me to feel for the controls, finding them without looking, minimizing distraction in the situations I probably least afford to be distracted.
No Capacitive Touch
Back then this was obvious, but in 2026, I need to make this point: my 2009 CL had no capacitive touch. The steering wheel controls were physical. The controls for the center screen are physical. Every major function could be operated without looking away from the road and was extremely predictable and intuitive.
Operation
The main control knob in this vehicle is a marvel of engineering. Instead of turning at fixed steps, it adapts to the context on the display.
When scrolling a long list, it can be turned continuously. When selecting from yes/no options, there are only two steps and then the knob mechanically locks. It can also be pushed up and down to access shortcuts.
The combination of these features is very powerful. It enables access to complex menus while minimizing distraction. For example, when there are two options available, the user doesn’t need to look at where the cursor currently is. They can feel it.
This even works for more complex operations as turning on the massage seats (that don’t have a dedicated button at the door). The user can select seats using the knob, which is always in the same place from the main menu, then select massage and select a program. This is a list of 4 programs that are always the same, so of the user likes they like e.g. the third one, they can scroll right three times. Of you would think of it a s selecting the second to last item which can be accomplished by scrolling all the way to the end and then going back one step. The adaptive controller makes that possible, and these complex tasks, if the user has memorized the steps, can be accomplished without looking a way from the road for even a second.
Rivian says they’ll have knobs like this starting with the R2 (although in the steering wheel). Mercedes-Benz had it in 2008 and yes, it works fabulously!
Ergonomic Considerations
Everything in this car is designed in a way that makes sense for a vehicle, instead of trying to adapt iPad UX for the sake of looking cool and maybe saving a few dollars in production. All the buttons are physical, meaningfully arranged and the icons are backlit.
The displays themselves are shielded from sunlight by hoods. This sounds obvious, but modern cars don’t do that, having to place the touchscreen closer to the user, sometimes resulting in blinding sun reflections.
Display Simplicity
The CL featured a digital speedometer display, yet mostly relied on a consistent, “analog” speedometer with a needle, drawn on that digital display. (except the night vision, that replaced most of the display with a black and white infrared view). When using adaptive cruise control (Distronic Plus in Mercedes terms), it would show a marker for the set speed, along with a band visualizing the delta in between nominal and actual speed. It couldn’t be more simple.
The Sad Future
Fast forward to today. Let’s look at the EQS, in comparison. Here, now, everything is on a touchscreen. The steering wheel controls are capacitive and the user, to go up and down a list hast to move their thumb up and down multiple times to scroll through lists.
When it comes to ergonomics and safety, the 2008-2013 Mercedes-Benz user experience is the one to beat. After this, everything went downhill, not only at Mercedes-Benz, but nearly all other car companies.
This is particularly sad, considering that I got ~13 mpg when commuting with this vehicle every day. An electric vehicle with the same user experience would be great, but unfortunately, car companies refuse to make that. The closest contemporary model is probably the Rolls-Royce Spectre.
But road safety concerns everyone. Why does it have to be a super-luxury to not get distracted when using basic vehicle functions? Why does not endangering people come at a premium nowadays?
None of those problems that Mercedes-Benz has solved in 2008 are obsolete. The sun still reflects off unshielded screens. Touchscreens are still distracting and cannot be operated without looking at them. Voice controls are still not a replacement for physical controls. Cars still don’t drive themselves and the Adaptive Cruise Control in my 2009 CL is not far from contemporary driver assistance. (It was way smoother than e.g. Teslas I’ve driven since then).
So if technology hasn’t changed, it looks like designers just got worse at designing automotive UX, for some reason.
Does that make me conservative? I love technology. As soon as there are self-driving cars, we can do all of these nonsense. But until then, Mercedes-Benz should bring back the amazing UX they had 2008-2013.
main image credit: @mariaxplores
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