Designing for Assisted Driving
10 min read
Role
Master's Thesis Student
Responsibilities
User research, Interaction design, Prototype development
Tools
Adobe Illustrator, VS Expression Blend, Processing
Company
Managers
Duration
7 months
Overview
VISES (Visual Interfaces for Safety and Enhanced Driving Experiences) was a graduate design project at VTI Sweden, aimed at making vehicle automation more intuitive. Focusing on Adaptive Cruise Control (ACC), I designed a dashboard interface that helps drivers stay informed about system limits and remain confident and in control.
The project was presented at SAFER Seminars and the Human Factors Collegium on Automation and Interaction Design in Gothenburg. A research abstract was also included in the proceedings of the 15th European Automotive Congress, held in Bucharest in November 2015.
Key Contributions
I conducted literature studies, user research, concept development and simulator evaluation at the Swedish National Road and Transport Research Institute (VTI).
Conducted Driver Research
Performed comprehensive study to understand drivers' needs and preferences regarding the communication of technical failures in ADAS.
Improved Driver Awareness & Safety
Designed an intuitive HMI that clearly communicated ADAS system failures based on mental model metaphors, reducing confusion, learning curves on system status and improving driver response times.
Simulator Prototyping and Testing
Conducted simulator prototyping and usability testing with drivers, to ensure users can quickly interpret system feedback and react accordingly.
Insight towards HMI Design
Offered insights into effective visual communication for safety-critical systems for future automotive UX best practices.
Background
As Advanced Driver-Assistance Systems (ADAS) like Adaptive Cruise Controls (ACC) become more common, there’s a growing need to design in-vehicle interfaces that help drivers understand what these systems can and can't do. Misinterpretation of their limits can lead to reduced trust, over-reliance, or unsafe interactions.
The project was an attempt at exploring how design can make system boundaries more transparent. The goal was to help drivers stay informed, aware, and confident while interacting with semi-automated systems on the road.
Understanding the Problem
Imagine you're cruising on a highway with the ACC engaged and everything feels normal. You find your vehicle getting closer and closer to the vehicle in front and suddenly, the ACC fails to engage the brakes. The car doesn't offer any alerts and there is a sense of panic and a delayed reaction. These are moments when relying on automation can be dangerous and you are left to guess what to do.
Cars are becoming more automated and automation is not risk-free. Simulator studies show that ACC failures can cause delayed responses and even collisions—43% in cases of partial braking failure.
This highlights the urgent need for HMIs that talk to us more clearly, making the switch between automated control and taking over by hand almost seamless. My goal was to design a system that assists the driver by conveying limits of automation in case of Adaptive Cruise Controls.
Role & Design Focus
This was a 7 month engagement with VTI and I was responsible for the entire design process, from research to prototyping and testing.
Conducting Driver Research
Researching driver behavior and failure patterns in semi-automated driving
Designing Alerts
Designing visual and auditory alerts for system malfunctions
Simulator Prototyping and Testing
Creating design prototypes and testing them in a driving simulator
Gather Feedback and Iterate
Helping drivers better understand system status, record feedback and iterate on designs
Research
The research phase set the groundwork for understanding how ACC failures affect driver performance and designing an interface concept that could improve driver understanding about these systems.
In the early weeks, my target was to gather as many user feedback as possible about these systems. So I conducted an in-depth review of literature for designing warning systems for cars and analysed participant feedback from SHADES research project. This helped derive insight related to ACC failure scenarios that shaped the user requirements for the interface concept. Below are some of the topics I explored.
Key Insights
The user feedback gathered during research provided key insights that shaped the design guidelines, defining how the interface should communicate failures and support both the driver’s mental models and physical reactions.
Drivers Have Different Mental Models
Drivers interact with ACC systems in different ways. Many misinterpret system capabilities or project more autonomy than is really possible.
Mode Confusion Is Common
Drivers have difficulty distinguishing between automated and manual modes, which result in improper responses or delayed takeovers during system outages.
Multimodal Alerts Improve Response
Audio alerts are preferred under stress and proved to be more effective. For prompt awareness, a mix of auditory and visual cues is essential.
Lack of Continuous Feedback
Drivers need ongoing, intuitive feedback about ACC status. Absence of this made it harder for them to maintain appropriate trust and attention.
Non-critical Failures Still Demand Actionable Feedback
Clear and timely cues help drivers understand what goes wrong and how to react, even in non-critical failures.
Trust and Complacency Are Dynamic
In order to match user expectations with system constraints, an interface must facilitate the proper calibration of trust.
The Design Journey
The process followed a Simulator-based iterative design methodology which is a human-centered design approach that leverages simulated driving environments to test and refine interface concepts in realistic, dynamic contexts—especially for safety-critical systems like ACC. The process is illustrated below. The Design Guidelines derived from the insights are also shown below.
Concept Development
With the guidelines and requirements in place, the next step was to brainstorm some ideas. The process began with a storyboard, using a driving scenario, to explore how the requirements could take form visually. Interaction flows and layout explorations were grounded in driver behavior, cognitive load limits, and instrument display design constraints.
Storyboarding scenario
The following driving use case scenario was considered while brainstorming concepts for the instrument cluster design. Below storyboard illustrates a situation when the ACC system fails to engage the brakes and the driver is left to guess what to do.
Design Direction, Moodboards and Layout Selection
The concept development phase began with the hope to finalise a dashboard layout. To achieve this, through explorations, two contrasting design directions were explored: traditional and futuristic using keywords and moodboards. These captured the essence of each style, helping align visual strategy with user needs and design guidelines. After several back and forths with experienced industry experts at VTI, a layout wireframe was chosen based on the guidelines.
Dynamic Emoji Interaction Concept
The first concept brainstormed on the layout was the Dynamic Emoji Concept. This was an exploration on how the warning design could be seamlessly integrated as emojis into the dashboard layout. Using the concept of emotional design, the idea focused on connecting with drivers' emotions by exploiting facial expression schemas to represent different system modes. Color coding served a dual purpose: indicating the current driving mode and signaling warning levels—helping the driver interpret both system state and urgency at a glance.
Adaptive Dashboard Concept
The Adaptive Dashboard Concept used the same design guidelines as the emoji concept but focused on a more traditional approach to the instrument cluster design. The gradients and alerts were adaptive, meaning they would change based on the system mode with clear message alerts and action animations to keep the driver informed.
Early Concept Evaluation
Both concepts were evaluated as a low-fidelity desktop prototype using a Show and Tell method with 10 participants, who were all employees at VTI and who had covered an annual driving distance between 15,000 to 20,000 km. The goal was to gather feedback on the design direction. The participants were shown the concepts after narrating the scenario and were asked to provide feedback on the overall design on a rating scale. The concepts were also evaluated based on design guidelines, technical feasibility and time-to-completion with regards to the project time-line. All the relevant icons for "set distance", "set speed" and conveying automation status were evaluated using an icon intuitiveness test.
Dynamic Emoji Concept
"I feel like emojis make the dashboard look too playful. When it comes to safety alerts, I want my car's interface to feel professional."
"For a car, emojis seem a little gimmicky. If the system employed smiley faces in place of warning symbols, I would have less faith in it."
"I don't have time to figure out what an emoji means at high speeds. I require something that is standardised and instantly identifiable."
Adaptive Dashboard Concept
"I like how it feels more contemporary yet familiar. It feels alive without being overpowering thanks to the gradients and animations."
"It still has the feel of an actual car dashboard. Because it appears serious but is still visually appealing, I have more faith in it."
"Not sure if I need the action animations. I'd prefer instant feedback rather than watching something animate."
Simulator Concept & Usability Testing
It was time to iterate the designs now. A simulator concept was designed based on feedback listed on the Dynamic Emoji and the Adaptive Dashboard concepts. The re-design edged towards a more traditional approach to dashboard design, having a more serious tone while still being visually appealing.
This was a dashboard concept with mode transitions integrated. The design used colour coding, earcons (audio warnings) and informing texts in accordance with the concept of affordances and mental model metaphors to convey different system modes to the driver. Different colours for different modes such as the color green for manual driving mode, blue for semi-autonomous or ACC OK mode and red for the System failure or ACC malfunction mode were used.
The goal of the evaluation phase was to determine how effectively the redesigned ACC visual and auditory warning system helped drivers detect automation failures and safely take back control.
The simulator prototype was evaluated against Nielsen's heuristics and an in-depth participant interviews, which were performed with 12 participants (6M +6F), aged between 25 and 51 years. All of whom had covered an annual driving distance between 15,000 and 20,000 kilometeres. The session was also recorded as audio for further analysis.
Key Findings
The key findings highlight how crucial it is to incorporate efficient visual and audio warning systems into automotive interfaces, especially in situations where ADAS malfunctions and the stakes are high. In order to take prompt action, participants showed a strong reliance on auditory alerts, indicating that audio notifications greatly attract attention at times when making decisions quickly is crucial.
Design Refinements
The design refinements were based on the feedback from the simulator usability tests and heuristic evaluation survey. Based on participant input, key areas for improvement were prioritized, leading to the following updates in the final concept.
Prolong Display of Alerting Texts
Ensure that warning messages remain visible for a longer duration after a failure notification, even as the driver takes corrective action (e.g., applying brakes) to allow for better interpretation of the situation
Auditory Feedback Enhancements
Evaluate and potentially increase the volume and clarity of audio warnings to better capture driver attention during critical situations. Implementing 3D sound notifications could be beneficial
Simplify Text Alerts
Modify the text used in alerts to be more concise, using clear abbreviations that can be easily understood at a glance (e.g., Cruise Control Error instead of longer messages) to improve readability
The Re-design
The alert messages and the typeface were updated to a more standardized one due to feedback on legibility of alerting texts. The updated type was from the German Institute for Standardization as a standardized, highly legible typeface for road signage, and adapted widely in transportation and technical fields.
Takeaways
- Do not slack in the early stages of your project. This is a graph plotted using the approximate working hours I checked-in at the end of every project week. I thought it would be an interesting insight to see what project task I dedicated most of my time to. As the project progressed and the deadlines were approaching, I ended up spending more hours at the office, struggling to keep up with my project plan.
- More focus on the Project Variables. The sharp increase in average working hours during the project's later stages could be attributed to prototyping and testing. However, this might have been avoided with more thorough research on the simulator infrastructure earlier on.
- Documentation is as important as your results and analysis. I know many of you under value the importance of documentation throughout the product design process. The small note I used for the project proved invaluable during the analysis and reporting stages.
- Avoid egocentric intuition fallacy. Even though the process of sketching concepts and coming up with new ideas is fun, doing it alone can be hard when you have to make key decisions during the course of your project. There is always the risk of ‘egocentric intuition fallacy’ as suggested by Landauer (1997) which makes designers believe that their perception of a system is applicable to everyone else. Avoid this by getting as much feedback as possible throughout the project.
Interested in learning more about this project? here is the link to the project report. Feel free to reach out to me if you have any further questions about the project. Also check out this video I made showcasing some snippets from the study and what my participants thought of the experience.
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