AI Insight
This research examined how people make moral judgments about everyday traffic situations by manipulating three factors: driver character, rule-following behavior, and collision outcomes. Across two studies using different presentation formats (text, video, and immersive simulations) with expert ethicists and lay participants, results showed that driver character most strongly influenced moral judgments, while rule compliance and consequences had weaker effects. Expert ethicists showed convergent judgments despite holding different moral theories, and presentation format significantly affected how participants weighed different moral factors.
Why it matters
These findings can inform the development of autonomous vehicle decision-making algorithms by identifying which moral considerations people prioritize in realistic traffic scenarios. The convergence among expert ethicists suggests it may be possible to create ethically-aligned AV systems based on shared moral judgments rather than competing theoretical frameworks.
Understand the Science
Investigating how different stakeholders evaluate traffic situations is essential for aligning autonomous vehicle (AV) decision-making with common-sense moral expectations. Yet, empirical studies on traffic moral judgment remain limited and almost exclusively focused on dramatic high-stakes situations. To address this gap, this paper presents two studies testing moral judgment in low-stakes ordinary traffic simulations. Drawing on the ADC model of moral judgment, both studies systematically manipulated key moral features: the character of the driver (Agent), adherence to traffic rules (Deed), and the presence or absence of a collision (Consequences). These components were embedded in a variety of stimuli, including textual vignettes, computer-generated video clips, and immersive audio-visual simulations. Data were collected from both expert ethicists (Study 1) and lay participants (Study 2). The results show that participants’ moral judgments were consistently and strongly influenced by the character of the agent, whereas the effects of rule compliance and consequences were less robust. The mode of presentation (textual vs. audio-visual) significantly moderated these effects in mixed ways, suggesting that different formats may be better suited to conveying specific types of moral information. Notably, Study 1 revealed that expert ethicists tended to converge in their evaluations of low-stakes traffic scenarios, despite endorsing different moral theories. This convergence supports the feasibility of designing AV decision-making algorithms based on shared ethical judgments. Furthermore, the findings highlight that character-based considerations play a significant role in moral judgment of traffic scenarios—alongside deontological and consequentialist reasoning.