Perceived safety and trust in SAE Level 2 partially automated cars: Results from an online questionnaire.

The present online study surveyed drivers of SAE Level 2 partially automated cars on automation use and attitudes towards automation. Respondents reported high levels of trust in their partially automated cars to maintain speed and distance to the car ahead (M = 4.41), and to feel safe most of the time (M = 4.22) on a scale from 1 to 5. Respondents indicated to always know when the car is in partially automated driving mode (M = 4.42), and to monitor the performance of their car most of the time (M = 4.34). A low rating was obtained for engaging in other activities while driving the partially automated car (M = 2.27). Partial automation did, however, increase reported engagement in secondary tasks that are already performed during manual driving (i.e., the proportion of respondents reporting to observe the landscape, use the phone for texting, navigation, music selection and calls, and eat during partially automated driving was higher in comparison to manual driving). Unsafe behaviour was rare with 1% of respondents indicating to rarely monitor the road, and another 1% to sleep during partially automated driving. Structural equation modeling revealed a strong, positive relationship between perceived safety and trust (ß = 0.69, p = 0.001). Performance expectancy had the strongest effects on automation use, followed by driver engagement, trust, and non-driving related task engagement. Perceived safety interacted with automation use through trust. We recommend future research to evaluate the development of perceived safety and trust in time, and revisit the influence of driver engagement and non-driving related task engagement, which emerged as new constructs related to trust in partial automation.

Investigating the effects of two fragrances on cabin comfort in an automotive environment.

BACKGROUND: For passengers in private or public transportation systems, comfort is a major interest. Available comfort models are already used to correlate thermal comfort to influencing factors. However, the available models do not other sensory comfort aspect and specific influences as fragrances and ambient light. OBJECTIVE: This publication investigates the impact of fragrances with "warm" and "cold" associated meanings on thermal and overall comfort perception. METHODS: Human subject trials (n = 47) were performed in different temperature-controlled environments following a 3×3 within-subject design considering ambient fragrance ("neutral scent", "peppermint", "orange & cinnamon") and ambient light as variables. RESULTS: Olfactory comfort is shown to have the larger effect on overall comfort perception, comparable in weight to the one of thermal comfort. The impact observed on thermal sensation was in line with the meanings associated the fragrances, whereas it was positive on thermal comfort appreciation regardless of the type of fragrance diffused. CONCLUSIONS: These initial results suggest that olfactory stimulations have the potential to positively impact thermal and overall comfort. The appreciation of the fragrance appears to have a major impact on these interactions and should be deeply considered in future research and features development.