Automakers take the risk of designing their own symbols for adaptive cruise control (ACC) and lane centring assist (LCA), some of them even using symbols from other driving assistance systems. Doing so exposes drivers to potential confusion and poses a threat to safety. A user-centred approach allowed us to gather information on ways to design intuitive symbols for users of automated vehicles. We invited drivers to a participatory design workshop to ideate and review existing symbols used for ACC and LCA. Here, we report our first step towards the development of recommendations for the design of driver-vehicle interfaces (DVI) of SAE level 2 and 3 systems.

Advanced driving assistance systems (ADAS) are now numerous, each relieving drivers of their responsibility for the control of different aspects of the driving task. Notably, adaptive cruise control (ACC) for longitudinal control, or lane departure prevention (LDP) and lane centring control (LCC) for lateral control, two variations of the lane-keeping assistance (LKA) system. Drivers must familiarise themselves with various symbols to correctly identify and activate the system they wish to be using and the existing standard graphical symbols for ACC and LKA are often replaced by manufacturers in favour of their own symbols. With a user-centred approach in mind, we previously conducted a focus group where drivers were invited to design their own symbols and discuss those symbols currently in-use. In the present research, we administered an online survey and analysed the responses from 328 drivers regarding different levels of knowledge about ADAS, to evaluate the usability of a selection of these symbols. Our results indicate that the standard ACC symbol would not be the most suitable of the four symbols tested, whereas, the standard LKA/LDP symbol was greatly confused with any of the four LCC symbols we tested, especially if hands were present on the symbol. Finally, drivers without prior knowledge of ADAS had more difficulties interpreting those symbols in general. Considerations for the development and evaluation of graphical symbols are discussed.

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Background Impairments in facial emotion recognition have been a hallmark of autism, which may contribute to the difficulty in social engagement and interpersonal interaction. Impaired facial emotion recognition in autism could be partly due to the asymmetrical perceptual bias to High Spatial Frequencies (HSF) information observed during visual perception. While Low Spatial Frequencies (LSF) convey coarse information, which would be critical for a fast analysis and categorization of emotional faces, HSF convey local information, which may serve a critical role in visual consciousness. However, to our knowledge, the effect of HSF on visual consciousness in autism has not been specifically studied so far. Methods Thirty-three adult autistic participants and 35 typically developing (TD) control participants performed an emotional attentional blink paradigm. Participants had to identify and report two targets (happy faces, T1 and T2) embedded in a stream of distractors (angry faces). The distractors between T1 and T2 were unfiltered or filtered in HSF or LSF. We used ANOVA to compare the impact of spatial frequency information on visual consciousness in the two groups of participants. Results TD control participants showed significantly reduced T2 accuracy (i.e., accuracy for the second target given the correct report of the first target T1) after unfiltered and HSF distractors compared to LSF distractors. As predicted, reduced T2 accuracy was observed after HSF distractors in the autistic group as compared to the TD group. Although we did not hypothesized, we also found reduced T2 accuracy after LSF distractors in the autistic group. The accuracy between the two groups did not differ regarding unfiltered distractors. Limitations Our sample was adult, high functioning and mainly late diagnosed. Therefore, our findings may not generalize to the whole autistic population. Conclusion Results confirm that HSF plays a critical role in visual consciousness in both TD and autistic participants. More importantly, autistic participants demonstrated impaired target detections after filtered distractors, suggesting that they have enhanced sensitivity for low-level characteristics, such as high and low spatial frequencies filtering. These findings are discussed in the context of the Enhanced Perceptual Functioning theory and predictive coding frameworks.

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