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In-Car HMI UX Evaluation & Benchmarking: Mercedes Benz E-Class

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As OEMs continue to increase the number of technologies equipped in their latest vehicles, the level of innovation they provide will only advance the landscape that surrounds them and, ultimately, pave the way for the Software-Defined Vehicle. However, the success of these technologies ultimately depends on their ability to deliver a seamless and satisfactory user experience. For OEMs, developers, and suppliers, delivering this experience will not only ensure successful product launches, but also secure long-term customer loyalty with the vehicle and its ecosystem of digital services.


Recognizing how these HMI features can positively, or negatively, contribute to the in-vehicle user experience is our In-Car HMI UX Evaluation & Benchmarking report series. Representing one of our best-selling, longest running, reports, it provides a comprehensive, analytical, assessment of the latest HMI systems launched around the world. For 2024, our UX experts will review and benchmark the systems provided in six recently released vehicles to understand who is leading in the space, and who is falling behind.


Following our article on the BMW X1 HMI UX report, this Insight covers the latest entry in the series which takes a deep dive into the 2024 Mercedes-Benz E-Class. While sharing its IVI and UX highlights, we will also be outlining the strengths and weaknesses posed by some of the saloon’s key systems and more deeply analyzing their implications on the end user experience.

A Closer Look at the Mercedes-Benz E-Class

For 2024, the E-Class presents a range of new, and improved, HMI features and technologies. At the forefront of this offering is the inclusion of Mercedes-Benz’s Superscreen, an integrated infotainment screen that spans the full width of the dashboard when paired with an optional passenger display. In a number of countries, the front seat passenger can use it during a journey to access and watch a variety of dynamic content from multimedia and video streaming services. To ensure the driver is not distracted by this content, an intelligent filtering concept powered by the in-vehicle camera ‘blocks out’ the display, allowing them to stay focused on the road ahead.


Supporting the Superscreen is a new software-centric electronics architecture, which utilizes a single processor to run the computing functions of previously separate feature domains – allowing MBUX and the screens to share a new, more powerful, central onboard computing system. On the display itself, a new compatibility layer brings compatibility for third-party apps to MBUX. This enables drivers to install games such as Angry Birds, access the social media app TikTok, join meetings through Zoom (which itself uses the in-vehicle camera), and browse the web using Vivaldi.


Key Takeaways

Early on in the HMI UX testing process, our experts discovered a key strength in the new ‘Zero-layer’ theme offered by the 2024 E-Class.


Presented as a new element in MBUX, the OEM’s proprietary multimedia system, the Zero-layer theme aims to minimize menu depth and levels throughout by providing users with quick access to frequently used features and apps from the top-level menu. It offers similar suggestions for varying features and shortcuts based on learned user behaviors and habits. When setting up the first user profile in the new E-Class, the driver must choose between the ‘Zero-layer’ or ‘Classic’ theme for MBUX in order to advance the profile creation process. Here, in order to help the user with their decision, MBUX provides clear, side-by-side, callouts comparing each theme and detailing their key properties. Our experts felt that this choice being presented at such an early stage in the user journey, and the level of personalization it provides, greatly supports the HMI UX – allowing the user to select a theme aligned with their unique needs and preferences. At the same time, they found that if the system had defaulted to the Classic theme, uptake for Zero-layer would likely be much lower since the user would have to find and activate it from within the vehicle settings.


On the other hand, our UX team found, when driving, some of the HMI controls proved to be overwhelming – a quality that could discourage their use altogether. Most notably, the buttons located on the steering wheel use a combination of capacitive touch technology and physical buttons to facilitate interactions with the system. During testing, our experts found that this combination presented a high risk of frequent misoperation, which could quickly lead to user frustration. At the same time, the number of icons that appear over the four bars around the steering wheel together create an overwhelming appearance. On the left side of the wheel, ADAS controls are clustered closely together that often require the driver to look away from the road ahead in order to be operated safely and accurately. This similarly introduces uncertainty around the operation of safety-critical systems, something that should be avoided wherever possible. To the right of the steering wheel are controls for the display, which our experts felt were complex to use while driving when compared to using the central touchscreen or voice recognition controls.


As they continued testing the new E-Class, conducting a deeper analysis of its HMI features, our experts found that it offered both strong foundations for a good UX in some features and room for improvement in others.

Our experts, for example, recognized the positive impact of the vehicle’s various delight features on user enjoyment, as well as their ability to create lasting talking points and a positive impression of the Mercedes-Benz brand. The team particularly found that the optional passenger display, the Active Ambient Lighting system, and MBUX’s in-vehicle gaming capabilities were key contributors to this positive experience among other delight features. The functionality of the Zero-layer theme enhanced this experience further, presenting a ‘dock’ along the bottom of the central display that provides efficient access to recently used features, based on repeated user habits, creates a shallow menu structure, and delivers a more intuitive experience for the user.


When testing the vehicle’s built-in navigation system, our experts discovered a key drawback of the HMI UX provided by the new E-Class. Here they found multiple inaccuracies within the system’s data – with a fuel station listed as a POI on the map despite it no longer being operational. Its destination arrival data presented similar inaccuracies, navigating the team to the premises next door instead of a desired supermarket. The integration of ADAS in the vehicle HMI also presented some room for improvement, with no headway shown in the cluster or HUD until it is adjusted. For new users, some of the icons used for these ADAS may seem jarring, while minor design inconsistencies in these icons may similarly pose the risk of distracted driving.

Next Steps

As shown through this article, the 2024 E-Class provides repeat customers and newcomers with a range of HMI features that together offer a personalized, software-centric, user experience. Within their testing and analysis of the vehicle, our UX experts enjoyed the variety of delight features presented across several domains, and also understood how complicated, overwhelming, controls for some of these features could hinder their UX altogether. However, the key takeaways and deep analysis shared in this article represent only a portion of the insights shared in the full E-Class HMI UX report.


Spanning more than 150 pages, it provides even deeper insights into the user experience of the new saloon’s features across several key domains, including ADAS, infotainment, navigation, and voice recognition. While scoring these features and functions against our proven evaluation methodologies, the report more broadly benchmarks the E-Class against the vehicles reviewed across our 2023 HMI UX reports, and the BMW X1 reviewed earlier this year.


Want to learn more about the latest in-vehicle HMI solutions, their impacts on the end user experience, and which vehicle offers the best user experience? Then be sure to secure your copy of our In-Car HMI UX Evaluation & Benchmarking series!


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