Bring back the knobs! Reintroducing physical controls in automobiles for safety and usability
Contemporary automobiles have increasingly adopted touchscreen interfaces for controlling many essential vehicle functions, replacing what were once physical controls such as knobs, sliders, and buttons. The new touchscreen interfaces, driven chiefly by cost considerations (a touchscreen is cheaper to manufacture than many electromechanical controls), mirror the interfaces of consumer phone and tablet apps and websites. The new interfaces often present digital replicas of physical controls, such as physical buttons or sliders becoming digital skeuomorphic metaphors on the screen.
While sleek and customizable, these interfaces have significant safety and usability challenges that should not be ignored. Multiple studies show that physical controls — buttons, dials, and switches — remain superior for reducing cognitive load and supporting drivers’ Situation Awareness (SA), a critical factor in safe driving. Touchscreen interfaces, however, suffer the same usability deficiencies that make texting while driving so dangerous. This essay argues for a return to some physical controls in automobiles with more judicious use of screens while emphasizing the role of interaction designers versed in human factors engineering in creating more human-centered systems.
The importance of Situation Awareness
Designing for Situation Awareness (SA) in automobile interfaces is crucial for enhancing driver safety, reducing cognitive load, and improving real-time decision-making. Yet, many automakers undervalue or misunderstand SA, often prioritizing sleek, touchscreen-heavy designs that bury critical information in deep menus rather than providing intuitive, glanceable displays.
Dr. Mica Endsley defines SA as “the perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future” (Endlsey, 2012).
Endsley’s model of SA describes a three-level scaffolded process:
- Level 1: Perception of Elements in the Environment — The ability to detect and recognize relevant information, such as visual, auditory, or sensory cues in a system or environment.
- Level 2: Comprehension of the Current Situation — Understanding the meaning and significance of perceived information by integrating it with prior knowledge and contextual awareness.
- Level 3: Projection of Future Status — Anticipating how the situation will evolve over time based on current trends, allowing for proactive decision-making.
Good HMI designs should prioritize glanceable, real-time data, minimize cognitive overload, and provide clear, actionable insights rather than overwhelming users with excessive information to support SA. Features like adaptive displays, predictive alerts, and context-aware automation enhance user decision-making, particularly in high-stakes environments like aviation, automotive, and military systems.
The touchscreen problem: non-tactility and distracted attention
Touchscreens inherently demand more attention than physical controls, as they lack the tactile feedback drivers rely on for muscle and spatial memory. According to an HMI study by the Swedish car magazine Vi Bilägare, drivers took up to four times longer to complete simple tasks on touchscreens versus physical controls. At highway speeds, this increased interaction time translates directly into a more significant risk of collisions. Research by Endsley has shown that distractions compromise Level 1 SA (perception) and Level 2 SA (comprehension), which are crucial for drivers to maintain awareness of their environment and make timely decisions.
Furthermore, systems like Apple CarPlay and Android Auto have been found to degrade reaction times more than alcohol or cannabis consumption. Texting or using apps while driving is extremely unsafe because these activities simultaneously impair visual, manual, and cognitive attention, completely diverting focus from the road. In contrast, drunk driving, though impaired, typically maintains some level of situational awareness. These findings underscore the need for interface designs prioritizing safety-critical functionality and usability.
The information architecture problem: navigating menus and cognitive load
The multi-layered, multi-modal information architecture of touchscreen controls, with its nested menus, tertiary screens, and dynamic interfaces, inherently increases cognitive load and operational inefficiency compared to the single-layered architecture of physical affordances. Touchscreens require users to navigate through hierarchical layers of information, often demanding visual attention to locate and activate controls, which interrupts primary tasks and divides focus. The lack of tactile feedback in touchscreens exacerbates this issue, forcing users to rely solely on visual cues, unlike physical controls that offer intuitive affordances and allow for non-visual operation.
Physical controls, such as dials or buttons, enable direct interaction with specific functions without the need for mode-switching or context awareness, making them faster, less error-prone, and cognitively lighter to operate in dynamic or high-stakes environments. By contrast, touchscreens introduce complexity and delay as users must interpret multi-modal interfaces, increasing the likelihood of errors and reducing overall task efficiency.
In the aforementioned HMI study by Vi Bilägare, the automobile interface that scored best overall amongst new cars (in 2022) was the Dacia Sandero. Although this vehicle has a touchscreen, it is relatively small, and climate controls remain physical knobs within easy reach for most drivers. However, the car that beat all others by a long shot was an old 2005 Volvo V70 with only physical controls and no touchscreen. The car that performed worst in these tests was the MG Marvel R, that features a large touchscreen where many features are hidden in menus and secondary or tertiary screens.
Physical controls: a solution grounded in human-centered design
Physical controls excel in usability because they leverage haptic feedback and allow operation without visual engagement. Human factors engineers understand that physical controls align with key human-machine interaction principles, such as direct manipulation and ergonomically designed affordances, enabling users to learn how to operate them instinctively while multitasking.
Endsley’s SA model also emphasizes that effective interface designs should support attention allocation and minimize cognitive overload. Physical controls naturally fulfill this requirement, allowing drivers to focus on road conditions rather than complex menu navigation.
How to use screens more effectively: learnings from the Glass Cockpit
The Glass Cockpit concept in airplane design replaces traditional analog dials and gauges with digital, screen-based displays that integrate and streamline critical flight information. Glass cockpits reduce cognitive load, improve situational awareness, and enable pilots to access essential information more efficiently by fusing data from multiple sources into configurable, easy-to-read digital interfaces. These displays can dynamically prioritize alerts, adapt to different flight conditions, and reduce cockpit clutter, making navigation, communication, and system monitoring more intuitive than traditional analog cockpits.
Glass cockpit screens in aviation solve many usability issues in automobile touchscreens by flattening the information architecture and prioritizing glanceable, context-aware displays. Unlike car touchscreens that often bury essential controls within deep menus, glass cockpits present critical data in a structured, at-a-glance format, reducing the need for excessive interaction. These screens dynamically adjust to show the most relevant information based on the flight phase, ensuring pilots can quickly access what they need without hunting through layers of settings. This approach minimizes distraction, improves situational awareness, and is a model for more intuitive automotive HMI design.
Addressing challenges in automation
Automation adds complexity to interface design. Endsley’s research on autonomous systems highlights the risks of “out-of-the-loop” phenomena, where drivers lose engagement and SA due to over-reliance on automation. Physical controls can counteract this by requiring active driver participation, maintaining engagement, and reducing the risk of cognitive complacency.
Additionally, as vehicles become more automated, interaction designers must ensure that information displays provide clear feedback on system status and automation boundaries, preventing SA degradation during transitions between manual and automated control.
Conclusion
The growing reliance on touchscreen interfaces in vehicles poses significant risks to safety and usability, particularly by diverting the driver’s attention to the UI, increasing cognitive load, and compromising situation awareness. Reintroducing physical controls for critical driving tasks can address these issues by providing intuitive, tactile feedback that supports drivers’ ability to perceive, comprehend, and project essential environmental phenomena. Screen-based UIs in automobiles could improve significantly by adopting glass cockpit principles, such as flattened information architecture, context-aware displays, and glanceable data, reducing menu navigation and minimizing driver distraction for a safer, more intuitive experience. To take a more human-centered approach to automotive interface design, automakers must steer away from current trends and instead prioritize safety and usability.
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Sources:
Boy, Guy A. The Handbook of Human-Machine Interaction. CRC Press. 2011.
Chen, Fang and Terken, Jacques. Automotive Interaction Design. Springer/China Machine Press. 2023.
Endsley, Mica. Designing for Situation Awareness: An Approach to User-Centered Design (2nd Edition). CRC Press. 2012.
Endsley, Mica. Situation Awareness Measurement: How to Measure Situation Awareness in Individuals and Teams. Human Factors and Ergonomics Society. 2021.
Guastello, Stephen J. Human Factors Engineering and Ergonomics (3rd Edition). CRC Press. 2023.
