Earcons to reduce mode confusions in partially automated vehicles: Development and application of an evaluation method

Monsaingeon, Noé; Caroux, Loïc; Langlois, Sabine; Lemercier, Céline · 2023 · openalex

DOI: 10.1016/j.ijhcs.2023.103044

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Summary

This study addresses the problem of mode confusion in partially automated vehicles (SAE Level 2), where drivers may fail to perceive or comprehend the status of automated systems like adaptive cruise control (ACC) and lane centering assist (LCA). Such confusion arises from inadequate mode awareness, defined through Endsley’s situational awareness model as a failure in perception, comprehension, or projection of system states. While visual interfaces are standard, they can overload drivers during critical transitions. The authors propose using earcons—abstract auditory signals—to indicate automation modes hierarchically. However, previous studies linked existing earcons to increased confusion. Consequently, the primary objective was to develop and validate a three-step laboratory evaluation method to objectively assess whether newly designed earcons effectively support mode awareness before integration into vehicle simulators. The researchers designed three distinct earcons representing transitions to Level 2 (full automation), Level 1 (partial automation), and Level 0 (manual driving). These sounds manipulated pitch, rhythm, and the number of notes to reflect the hierarchy of automation levels, adhering to established sonification guidelines. The evaluation method comprised three experiments. Experiment 1 assessed perception using a same/different discrimination task with 35 participants. Experiment 2 evaluated comprehension in isolation via a cued recall task, where 528 participants associated earcons with visual icons representing automation modes. Experiment 3 tested comprehension under cognitive load by requiring participants to perform the cued recall task concurrently with a parallel visual task mimicking driving demands. The results demonstrated that the earcons were efficiently perceived and comprehended. In Experiment 1, participants correctly discriminated between all earcon pairs at rates significantly above chance (mean accuracy ranging from 0.96 to 0.99), confirming that the manipulated acoustic parameters allowed for clear differentiation. In Experiment 2, participants correctly identified the automation mode associated with each earcon at high rates (median accuracy of 0.80 for L1 and L2, and 1.00 for L0), significantly exceeding the chance level of 0.33. Although the text provided is truncated before the full results of Experiment 3, the abstract indicates that the earcons provoked only a small decrement in visual task performance, suggesting they do not significantly interfere with parallel visual processing. The study concludes that the proposed earcons, designed to reflect the hierarchy of automation modes, successfully meet the perception and comprehension requirements of mode awareness. The three-step evaluation method was validated as an effective tool for objectively assessing auditory signals in a controlled laboratory setting. This approach allows designers to verify that auditory cues contribute positively to situational awareness before deploying them in dynamic driving simulators or real vehicles. By ensuring earcons are distinct and comprehensible without imposing excessive cognitive load, this method supports the development of safer multimodal interfaces for partially automated driving systems.

Key finding

The developed earcons were efficiently perceived and comprehended by participants, both in isolation and during a parallel visual task, validating the proposed evaluation method for assessing auditory signals in partially automated vehicles.

Methodology

lab_experiment

Sample size: 563

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via scout_discovery on 2026-05-08.

Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.

Topics

Ranked by relevance to this paper. Hover a topic for its definition.

• auditory warnings
• mode awareness
• auditory
• multimodal feedback
• voice interaction
• situational awareness

Information type

What kind of knowledge this paper contributes, grouped by family — independent of topic (what it is about) and method (how it was studied).

• Applied Guidance: design guidelines
• Theoretical Contribution: conceptual framework